I've been working off and on at this for hours now so it may look a total mess.
I've done a little research (which mostly means hitting up Wikipedia, I'm afraid - its pretty early in the day for me). Feel free to shoot down any ideas that don't particularly make sense. Most of what I've done so far is simply to come up with ideas for resources - there aren't much in the way of Warm Clothes winter promotions on the whole here, yet - mostly its just ideas on how to give some of the less useful resources purposes for being.
NEW NATIVE CULTURE IDEA: This is a very awkward idea but what if building the Wonder for a culture grants an otherwise unobtainable tech, which then enables you to build a national wonder that grants the resource. This means that OTHER nations could perhaps gain access to the tech through tech diffusion, which would enable them to build the national wonder to, simulating emigration. This particular tech, however, should diffuse very slowly in the early game as people don't travel far but increase with every major transportation tech (ocean going ships, automobiles, planes) - so there is a chance, say, that people can gain knowledge from neighbours crossing the border. Obviously, border techs should influence how likely this is to happen - open borders making it more likely, closed borders decreasing it. If this is the case, then, closed borders should have some bonus. I think some of the small cultures (such as Aka and Basque) might migrate very slowly, if at all. Others (such as American or Chinese) might have less of a problem. If its possible to influence the diffusion at all, maybe its easier for cultures to share with those of the same backbone culture (German and Austrian, for instance).
I've never quite understood what national wonders should be limitted in terms of x per city. If that limit is lifted, it could make this idea work - I honestly don't think that a microlith workshop or learning to tame fire should stop a city from later building the DMV or a heroic epic. I'd kind of personally see national wonders either made unlimited, alongside the option for national units (which I actually have off) and great wonders (which I have on). If not, maybe make the cultural "national wonders" and early national wonders which really shouldn't interfere with late game infrastructure into buildings that have a limit of 1 per civ but no influence on national wonder availability.
An alternative is to perhaps make each "wonder" of a native culture actually grant multiple instances of the resource so it can be traded, thus enabling the sharing of culture and ideas. Just brainstorming though.
Small Cultures and Nationalism: I'm just wondering how cultures should interact with nationalism. I think, perhaps, cities might produce more culture but more revolutionary spirit (possibly unhappyiness or increased rev) through separitist ideals. The units they train, however, should probably qualify for a smaller version of the Motherland Promotion - say +1 first strike, +10% strength in own territory, +10% city defence)
Herds: Is it possible that instead of outright providing Carcasses, Herds provide the relevant resource? Like, Bison - Herd providing Bison and then Bison Hunter's Camp requiring either a local source of Bison or the existing herd to provide Carcasses? Once herds are established, wouldn't it be possible to train the relevant Subdued Animal, thus enabling me to take herds elsewhere and set them up? As is, I think the Animal -> Carcass -> Hide/Bones line is possibly the most developed, useful and coansistent.
Anyway, for possibilities for the various unused or less important resources. I skipped over ones I had no suggestions for or felt had plenty already.
Aborigine - Rock Painting (Building, Requires Natural Pigments, requires Rocky terrain or Peak or Outcropping, +1 culture, +1 happiness, +3 culture with discovery of Archaeology, +2 Culture with Peak or Outcropping to make more valuable)
- Ayers Rock/Uluru (Wonder. Requires Peak near city, +1 Happiness, +3 culture, gives Rock Painting in all cities. Does not require aborigine but gains +50% bonus to build from it. +2 gold from Tourism)
Ainu - Ainu Village (Building, requires Tattoos, +1% Culture with Tattoo Parlour, +1 Food with Deer, +2 XP to units trained here if Poison is available, trains Surku 20% faster)
As an aside, Tattoo Parlour requires Dye as is, yet gains +5% culture with Dye. Remove Dye requirement, first of all, keep +5% bonus.
Aka - Aka Hunters (Building, +0.1 Health per unimproved jungle within city limits, +0.5 food per unimproved jungle within city limits, trains Pygmy Warrior 20% faster)
Almonds - Required for Nuts already. Possibly Massage Parlour (Building), which adds a little culture, happiness and possibly a point of health - Almonds aren't required for it, but might grant a small extra bonus to health or happiness (apparently Almond Oil is used in massage?)
Amber - +1% gold with Jewellery, +1 Guld with Bazaar, Market, etc. line. If we go down the weird sciences route...
Jurassic Park (Wonder, requires Fossils, Amber, Genetics. +25% science, +100% gold in city, +1 Happiness in all cities, +1 Great Scientist Point per turn. Each tile surrounding city produces 1 less food and 3 more gold, to represent space taken up by park facilities?)
American - +1 Happiness with Mall, Mall of America (wonder, requires Refridgeration, requires at least 5 Malls, America gains +50% to build, adds Mall to all cities over Size 20 automatically)
Ammunition - already has plenty. Ammo Dump (Increase flammability, -10% defence, -5% Espionage, +33% build Gunpowder Units, +25% build Siege, Wheeled and Tracked Units, +10% build Early Fighters and Bombers). Possibly Naval Mine units - mine warfare seems to have nothing associated with it yet.
Ancient Relics - revealed much sooner, say during Middle Ages, to represent selling and scavenging of things abandoned by many of the classic empires - aquaducts and roman manors in post-roman britain were subject to scavenging, even for their masonry, as it was often easier to just steal blocks from an old house or fort than to quarry out new ones. Dig Site still requires Archaeology, but simply having Ancient Relics within the City limits enables the following: Scavenger Quarry (+20% to building production, +1 Food on Ancient Relic Sites, +1 Hammer on Ancient Relic Sites, -1 Gold on Ancient Relic Sites). Perhaps make Treasure units (spawned from Ruins) be able to, when still on Ruins, sacrifice themselves to create a source of Ancient Relics to represent scavenging.
Apache - Apache Teepee (Requires Plains, Shelter Building, Skinning, +1 Food, +1 Hammer, +1 XP for Archers and Mounted Units)
Apache Wickiup (Requires Plains, Shelter Building, Bark Working, +1 Food, +1 Hammer, +1 XP for Archers and Mounted Units)
Apache Hogan (requires Desert, Shelter Building, Stone Building, +1 Food, +1 Hammer, +1 XP for Archers and Mounted Units)
Apple - Already does plenty not listed on it's page (alcohol, etc.) Perhaps things like Distillery should not require local resources but access to resources at all?
Arabian - Arabesque Architecture (Building, Requires Architecture, +1 GPP Artist, -1 Hammer, +5% Culture)
- One Thousand and One Arabian Nights (Wonder, Requires Literature. Does not require Arabian but gains +50% to build from it. Possibly ahistorical, unfotunately, but its history is complex. +1 Happiness in all cities, +25% culture in city, +2 GPP Artist. Possibly requires Paper?)
- House of Wisdom (Wonder, Requires Literature, Does not require Arabian but gains +50% to build from it, +20% Science, increase rate of tech diffusion, halves cost of Language civics, obsolete with Universal Translator. Possibly requires Paper?)
Armenian - +1 Happiness with Dance Hut and Dance Hall
Artsakhan Carpets (Building, Requires Trade, Cloth, +2 Gold, +1 Culture, +5% gold with market-line buildings)
Assyria - Already has cultural wonder - possibly make it available to all cultures and give it +50% to build wonder instead.
Australia - ANZAC Spirit (Wonder Requires Automatic Weapons, does not require Australia but gets +50% to build. If New Zealand gets a culture too, they should also gain +50% to build. Becomes obsolete quickly, possibly with Mechanized Warfare, representing the fact that it got quickly disbanded and reorganized. +1 Culture, +2 XP to units in all cities, -20% War Weariness in all Cities, +10% to train gunpowder infantry in all cities - if possible, make it increase to +35% during wars)
Austria - House of Hasburg (Wonder Requires Divine Right, does not require Austria but gets +50% to build. Increased relations with all civs, -25% maintenance for number of cities? +1 Culture in all cities. If "wedding" based events occurr, gain a Great Artist)
Automobile - DMV, modern roads, etc. should require Automobile just as a matter of fact.
Aztec - Grant bonus to building Chichen Itza? +1 Happiness in Cities after Captured Slaves are Sacrificed, +1 Happiness and +2 XP to Melee Units with Sacrificial Altar
Babylon - Babylonian Mathematics (World Project, Babylon gets +25% to build it, requires Babylon + Writing to give head start - others require just Mathematics. Producer gets 1 Great Scientist, all cities get +2 Beakers and +5% science, all cities in the world get +1 Beaker. If the owner did not have Mathematics researched, gain Mathematics.)
Bamboo - already does plenty, but perhaps should do most things wood can (can't hovels and huts be made from bamboo?)
Bandanese - initial wonder should require Culture (Asian), volcano maybe (volanic islands), definitely coast and possibly reef. Almost certainly should require Spice due to Nutmeg Trade.
Nutmeg Monopoly (Building, Requires Spice Trade, Spice resource in vicinity. Allows 2 Merchants, +5% gold, grants Spice resource. The reason being this potentially increases their supply which means they can conduct more trading)
Banana - already used for multiple things not listed on page (as buildings require it in vicinity)
Barley - should be available as alternative resource for alcohol and fullfill similar options (Strategic Grain Reserve, etc.) that Corn and other grains do. Should also have associated grain farm to produce grain for biofuels.
Barrels - +20% to build any building that involves alcohol (distillery, bars) or simple storage (granary, for instance), +20% to build wooden ships, +1 Health (due to safe storage), +10% to build Civillian units (transport of goods for workers and freight)
Baskets - +10% to build things like granaries, +10% to build Civillian units (transport of goods for workers and freight)
Basque - Requires Culture (Europe)
Basque Equality (Requires Monarchy -tech.+1 Happiness, +1 Culture, +5% Food Stored)
Guernica Mural (Requires Cubism, perhaps?, Wonder, +50% to build with Basque but not required, +2 GPP Artist, +50% Culture, enemies suffer +50% War Weariness, spawns Great Artist, +1 Culture in all Art Galleries)
Beads - Not really sure - already have economic use through trade posts/marketplace. I feel something should be done with them, however.
Bengali - Bengali Waterways (Building, Requires Steam Power, +0.5 Merchants per River Tile or Marsh Tile)
Benin - Dahomey Militarism (Building, +10% Military Unit production, +2 XP, +2 more XP with Apprenticeship)
Berber - Corsair's Landing (Building, Increases Criminal activity, Wooden Ships trained here gain +2 XP and begin with Coastal Assault I promotion. +20% to build Barbary Corairs)
Bermese - shouldn't that be Burmese? Possible units to include Ghurka. Unsure about unique structures and other bonuses, however. Perhaps Burmese Pagoda?
Berries - as with other fruit, they already have a general application. Should provide bonuses to things like Bakery.
Bicycles - +1 Health, +1 Happiness with Extreme Sports and Tourism?
Biopunk - Not really my place to say as this is a part of the alt-history stuff that I don't know much about. How do we explore alt history in game, anyway?
Bison - Already has existing dynamic, possibly be used to train Subdued Bison so herds can be set up elsewhere?
Books - Books are used by buildings that primarily already can be built (due to having paper or tablets). As a result, it might make more sense to give Books a +5% beakers on buildings like libraries, schools and monastaries for the ease they provide. Books should also perhaps provide a bonus to Happiness in scientific buildings but suffer -2 to Happiness, say, with Intolerant (civic) due to the decreased control over heretical beliefs.
Brass Instruments - +1 XP to training units (military regimental band, morale boost)
Brazilian - Sabma (Wonder, requires Radio, does not require Brazillian but gains +50% production. +2 GPP, 1 artist slot, +25% culture, gives 2 Hit Singles)
Bread - As an enormous staple food, perhaps it should provide increased Food with the Market-chain of buildings.
Bullion - Possibly increase trade route yield on trade buildings by +5% due to the increased ease of carrying and storing precious metals
Byzantine - +50% to build Hagia Sofia, perhaps
Conversion of Constantine (Requires Theology, +50% to build from having Byzantine, Religious Conversion causes no anarchy but cannot be performed more than once in 100 turns. +1 Happiness in all cities with State Religion, +1 Happines in all cities with State Religion for controling State Religion Holy City, +3 Happiness in State Religion Holy City, +50% production in all cities to build Missionaries, Missionaries generate small amount of culture when they add religion)
Canadian - Already has some wonders tied to them.
Cantonese - Bruce Lee (Wonder, requires Radio, does not require Cantonese but gains +50% production. +2 GPP, 1 artist slot, +25% culture, gives 2 Hit Movies, units trained here gain Martial Arts III)
Carbon Dioxide Ice - No idea of yet, especially with it being tied to space techs.
Carib - Ritual Cannibalism (wonder, requires Sacrifice cult, does not require Carib but gains +50% production. Units in City gain +2 XP, nearest city gains culture, hammers or food when enemy units are killed, akin to hunting - not standardised like it though, just random returns. Enemies suffer +50% War Weariness, obsoletes with a later medicine tech)
Carthaginian - Hannibal's Army (building, requires elephants in vicinity, Elephant Riding and Military Training, +3 XP for Units, Melee, Mounted and Ranged Units begin with Mountaineering Promotion)
Celtic - Most of the Celtic bonuses in terms of wonders should be moved to Scottish
The Book of Kells (Wonder, requires Christianity, does not require Celtic but gains +50%. +2 GPP, can make 1 Artist Slot, 1 Priest Slott, +25% culture, +25% research in city, +5% research in all Christian Monastaries, +25% production to build Christian Monastaries in all cities)
Celtic Art (Building, requires Chiefdom, +1 Culture, can make 1 citizen into Artist)
Ceylon - Epic of Ramayana? Both Ceylon and India would have a bonus to produce this and it would require Hinduism in the city. Unsure of bonuses.
Charcoal - as suggested in the comments, enabling people to settle in Tundra, Ice and Permafrost may be interesting or possibly enabling terrain that is otherwise unproductive to at least provide 1 gold, akin to deserts.
Cheese - Long lasting foods, +10% to build Settlers?
Cherokee - Medicine Man's Hut (Building, +1 GPP Great Healer, +1 Culture, +1 Health)
Cheyenne - Cheyenne Village (+1 food from Bison sources, +1 Hammer from Horses, +1 XP)
Chocolate - Grants bonus to happiness, possible penalties to health as time goes on
Chola - Chola Contentment (Building, +1 Happiness, +1 Culture)
Chumash - As it seems the Chumash were capable ocean goers, recommending a low-strength ship that can cross oceans prior to middle ages. Reason I suggest low strength is to prevent the civ from being able to travel the world too easily - something strong enough to get by many animals but apt to get destroyed by foreign fleets and barbarians if it explores too far along unsure coasts.
Clockpunk - Alternative tech, already under work. Because of the DaVinci nature of it, I might suggest adding a Clockwork Tank and Clockwork Copter as well, granting primitve flight. If the latter happens, I think Ranged and Gunpowder units should probably have limitted AA capability - I mean, in the first world war, ground infantry were capable of potentially taking down planes. I only suggest this to prevent a Clockwork Copter being indestructible.
Clothing - Uniform and Warm Clothing options already suggested, perhaps make them as cheap buildings that require all relevant resources.
Coffee - Already somewhat relevant for buildings - perhaps add Cafe building which requires either Tea or Coffee.
Comanche - Commanche Wars (Building, requires Cavalry Tactics +2 XP for Mounted Units, Mounted Units begin with Flanking I)
Copper Wires - Should be somewhat integral for many modern buildings, including power plants, telephones, possibly telegraph offices considering they enter with telegraph. Telegraph Office should probably be cheaper than Telephone Network but provide fewer bonuses due to the time lag involved.
Cotton - Possibly Cotton Gin to increase gold yield from Cotton Planations
Cree - Cree Wigwams (Building, +1 Hammer, +1 Gold, +1 Culture)
Cree Canoes (Building, +0.5 gold per river tile, +1 Culture)
Cuban - Cuban Cigars (Wonder, requires Mercantilism, Tobacco in city vicinity. Does not require Cuban but gains +50% production. +2 GPP, 2 Merchant Slots, +25% Gold, gives extra Tobacco Resource, Tobacco Resource gains +1 Happiness and all Tobacco resources produce +2 Gold for Civ)
Suggested combinations:
Building - Warm Clothing (clothes + furs) could grant promotions to increase defence in tundra, ice and permafrost and remove damage from terrain
Building - Water Supplies (Barrels + Lake or River) could grant promotions to increase defence in deserts and remove damage from terrain
Building - SCUBA Gear (Lake, River or Coast + Clothing + Steel) could grant promotions that give Espionage Units the ability to enter coastal tiles and Special Forces-type units Amphibious.
