1 - There's always a better option available
2 - Good for certain civs, under certain circumstances
3 - You can never go wrong with these
4 - A really good pick with the right strategy
5 - Excellent, will always be good under any circumstance
2 - Dance of the Aurora: Holy Site districts get +1 Faith from adjacent Tundra tiles. This one is really good for Russia. Otherwise, meh.
2 - Sacred Path: Holy Site districts get +1 Faith from adjacent Rainforest tiles. (A decent option for Brazil, but otherwise, nothing spectacular. The only other jungle civ can't even build holy sites.)
1 - Monument of the Gods: +15% Production to Ancient and Classical era Wonders. (For role-playing values, it's useful for China or Egypt, but I personally never go for early wonders, so pass)
3 - Lady of the Reeds and Marshes: +1 Production from Marsh, Oasis, and Floodplains. (A decent early-game boost. Definitely useful if you play as Nubia or Egypt)
1 - God of the Open Sky: +1 Culture from Pastures. (Nah, that extra eight culture isn't going to cut it)
1 - Desert Folklore: Holy Site districts get +1 Faith from adjacent Desert tiles. (I suppose this is the rebound from being the best Pantheon in Civ 5. Only good if you have Petra.)
1 - River Goddess: +1 Amenity to cities if they have a Holy Site district adjacent to a River. (If I build Holy Sites, I look for adjecency bonuses, not amenities.)
5 - Divine Spark: +1 Great Person point from Holy Site (Prophet), Campus (Scientist), and Theater Square (Writer) districts. (Excellent in every circumstance, especially if you want a religion on higher difficulties. my default pick)
2 - God of the Sea: +1 Production from Fishing Boats. (Really strong with Indonesia on Island Plates, in combination with Kampungs. On Land Maps though... meh.)
3 - Goddess of the Hunt: +1 Food from Camps. (One can never go wrong with a bit of extra growth. Good in cities with a good surplus lower than 10.)
4 - Fertility Rites: City growth rate is 10% higher. (Same, but this one is better because it's +1 food for every 10 food in a city, in every city, regardless of terrain RNG.)
2 - Religious Idols: +1 Faith from Mines over Luxury and Bonus resources. (Tile yields should never be your principle source of faith, but it can be good if you play as Greece with Legendary start)
1 - God of the Craftsmen: +1 Production from Mines over Strategic resources. (Tried it once, thinking it applied to Copper. Never again.)
2 - Goddess of Festivals: +1 Food from Wine, Incense, Cocoa, Tobacco, Coffee, and Tea Plantations. (A bit of extra growth is always nice, but less reliable than Goddess of the Hunt)
2 - Oral Tradition: +1 Culture from Banana, Citrus, Cotton, Dyes, Silk, Spices, and Sugar Plantations. (Bananas are very common, so the extra culture can stack. But like above, not very reliable.)
4 - God of the Forge: +25% Production toward Ancient and Classical military units. (Excellent for Scythia, who can get this pantheon very early thanks to the Kurgan. Indonesia and India also get faith boosts, making early warmongering more viable for them as well.)
2 - Initiation Rites: +50 Faith for each Barbarian Outpost cleared. (This should be good for Sumeria, who should prioritize clearing Outposts regardless of strategy.)
2 - God of Healing: Increases Healing by +30 in your Holy Site district, or any adjacent tiles. (This bonus is useful for defense. I'd say Khmer benefit from it the most as their HS should be placed aggressively for the culture bomb, followed by Japan and Russia who get cheaper HS.)
5 - Religious Settlements: Border expansion rate is 15% faster. (More territory is NEVER bad. Trajan in particular should love this one, with his free monument.)
4 - Goddess of the Harvest: Harvesting a resource or removing a feature receives Faith equal to the other yield's quantity. (I never picked this one, but I should try it. We're talking about 30-80 faith per harvest. This is a pretty substantial amount, given how often I harvest non-river forests, stone and jungles.)
3 - Stone Circles: +2 Faith from Quarries. (Quarries are inferior to mines, but with the prevalence of stone it's not half as bad.)
2 - God of War: Bonus Faith equal to 50% of the strength of each enemy unit killed within 8 tiles of a Holy Site district you own. (Eight tiles is a massive range, but 50% strength isn't really enough, since religious units easily cost over 300 faith a piece.)
I got carried away, and created a somewhat terrain-less landscape. IMO the pantheon is way OP, and needs to be seriously nerfed. It's probably "realistic", if you want to model what a good cult could do as a government (no names please), but I found it limiting my options to, 1) "burn him @ the stake!" versus, "off with his head!" Too easy to crush everything w/this pantheon, assuming you stack things so that (most) everything revolves around religion. 
I have no problem getting Earth Goddess or Goddess of the Harvest @ King. 
On Emperor, I really have to push hard to get the first Pantheon, and often miss it if another Civ. gets a relic or other early Faith. The difference between getting First (or Second) Pantheon (as well as a decent Religion) is HUGE! 
I still got a Pantheon, but it was "God of the Sea," (2 of the 3 cities were coastal, and near numerous aquatic resources...NICE) ! 
NOTE: I have to admit, I saved the game so I could replay it if my attack failed, but it WORKED! 
