I had a Meso Cav civ concept.
Tarrasques
Naitve American Cavalry civ
Unique Unit:
-Outrider: Spear-weilding Cavalry unit that has low armour, costs only food, but has very high HP and extra damage vs Cavalry.
Unique Technologies:
-Spanish Horses: Cavalry units have +50 HP
-War Arrow: Archer and Cavalry Archer line units +1 Range + 20% Attack Speed
Civ Bonus:
-Farms built instantly
-Elite Skirmisher free
-Eagle Scout line units +1 Move Speed on Castle/+2 Move Speed on Imperial Age
-Barracks upgrades cost no Gold
Team Bonus:
-Spearman line units +2 damage vs Infantry
Production and Research:
-Barracks: No Halberdier, no Two Handed Swordsman, no Elite Eagle Warrior
-Archery Range: No Heavy Cavalry Archer, no Hand Cannonneer
-Stables: N/A
-Docks: No Fast Fire Ship, no Heavy Demolition Ship, no Cannon Galleon
-Siege Workshop: No Siege Ram, No Heavy Scorpion, no Bombard Cannon
-Castle: No Hoardings
-Monastery: No Faith, Sanctity, Block Printing, Atonement and Herbal Medicine
-Blacksmith: No Plate Barding Armour
-University: No Masonry, no Architecture, no Guard Tower, no Bombard Tower
Economy:
-No Crop Rotation, no Stone Shaft Mining
Notes:
This would be a civ that is heavily dependant on their Castle UU, and their Cavalry Archers/Arbalests, to keep presence on the battlefield. They could do very fast rushes with their Barracks units, but they would not translate well into Imperial Age, though the Archery Range + Castle units combo would be a good endgame for them.
I purposefully left them with very weak defenses, as historically the Tarrasques were almost always on the offense, and did not mount particularly harsh resistance to the Spanish, when they finally came for them.
A Tarrasques player will want to raid and make the enemy fall behind, rather than try to Age up and go wide on the lategame, where their tech tree is lacking.
Outriders would be a good cross between Camels and Hussars, and be trained up from the Castle Age. Along Trebuchets, Arbalests and Siege Onagers + the easily upgraded trash Pikemen and Eagle warriors; Tarrasques would come out of Feudal with fury, and go to Imperial on the front foot, if they manage to cripple their enemies.
This would be as civ designed more for 1v1, rather than Team games, but the Team Bonus would be welcomed by Turks, Bizantines and Japanese alike, because all of them field Spearmen line units, and Turks would probably like one of their most basic units to atleast get a boost.