Note: This ones are taken form an anonymous’ comments from the AOE wiki, so could be diiferent in the final patch, but who knows:
Bulgarians:
- Blacksmith and Siege Workshop technologies cost 50% less food. (New)
- Blacksmiths work 80% faster. (Up from 50%)
Another nerf
Celts
Their infantry speed bonus will start in the Feudal Age, instead of the Dark Age.
Khmer:
- Battle Elephants move 10% faster (Down from 15%)
OH another one another one:
Koreans:
- New Civ Bonus: Free archer armor upgrades.
- New Castle Age Unique Tech: Watch Tower line +2 range. Replaces Panokseon and the current +Tower range bonus. Tower upgrades are still free (Bombard Tower requires Chemistry.)
Tatars (OH boi):
- Town Centers spawn 2 sheep starting in the Feudal Age. I assume this includes the starting TC “Centers” includes all new Town Centers
HMOG there’s more:
Portuguese:
- Technologies research 30% faster, unknown if it affects aging up
Those are the only ones apparently leaked, other than Nili’s leaks of Cav Archer buff and Viking nerf