Some custom icons that I designed for future civs in the game:
Embers Clan (Orcs):
UA: Clans of Fire and Ash - Start allied with humanoid barbarians until they reveal Iron, can buy barbarian humanoid units with gold (no maintenance), can convert humanoid barbarian camps to cities with Renown (Culture), all combat units start with the Subdue I promotion (+25% to convert unit upon defeat) and generate +1 Renown (Culture) for every point of combat experience gained, Animal Cages and Beast Pens produce double resources (which are created from subdued animal barbarian units)
Fae:
I might shamelessly borrow much of Bane's
Warlords Battleciv TC Fey civ for Bloodmoon's Fae civ traits....
Crusaders:
UA: Holy Defenders - Melee units have +25% defense within their borders, +30 HP healed per turn adjacent to a friendly city, gain faith for killing enemy units within 4 tiles of a friendly city
UU: Crusader - Similar attributes to a Pictish Warrior, but is stronger and can only be purchased with faith. Requires no maintenance. It has a limited promotion tree and cannot be upgraded. Can be disbanded for faith in friendly territory or donated to City States for Influence.
UI: Stronghold - Replaces Trading Post, produces +1 Gold and +1 Faith. Cannot be adjacent to a city or another stronghold. Has a 2% chance per turn of creating a Crusader whenever the civilization is at war.
Wood Elves:
UA: Sacred Grove Guardians - City connections through forests as roads. Unimproved forest tiles produce +1 Food/Culture/Production. Recon units start with the Woodsman I+II promotions (double movement rate in forest, +25% strength in forest and forest as roads); builders can create forest on unforested plains, grassland, hills, and tundra terrains
UU: Ent - replaces catapult, stronger and has a +50% defensive bonus in forests (but -25% city attacks), only spawns in forest tiles within civ borders when at war (5% chance per tile), costs no maintenance
Horselords:
UA: Mercenary Horselords - Mounted units are similar to the Keshik (except no ranged attack) but available at Horseback Riding. In addition, units can be sold to City States for gold and double the Influence. Great Generals are per the Khan great person (but can build a Warhorse per below instead of a citadel).
UB: Livery Stables - Replaces stable, same as Poland's Ducal stable
UU: Warhorse - As Cataphract, but stronger and has no city attack penalty. Includes the March promotion plus the Khan Leadership and Enhanced Medic abilities. Can only be built by consuming a Great General
Sea Marauders:
UA: Harbors of the Tempest - All coastal tiles produce +1 Gold/Food. +1 Movement and Sight for all naval units and all naval units can enter ocean tiles at game start (per Polynesia). All Naval melee units start with the Prize Ships promotion.
UB: Quay - +10% Production in the city. 1 Maintenance. May only be built in coastal cities. Allows the Wharf improvement.
UI: Wharf - +1 Production, Food, and Gold, can be built on coastal tiles adjacent to land owned by the city. Cannot be built next to a city or another Wharf. Additional +1 Production/Food/Gold with cities containing a Port.