There are a few that come to mind.
Byzantines, just the extra HP on buildings is insane, but also having cheaper counters is great.
The extra healing on monks also helps here.
Teutons, I mean free murder holes, extra garrison space, infantry shoot arrows, castles that can outrange bombard cannons, monks with higher healing rate, and an insane eco to boom with while you defend.
Koreans/Japanese come to mind if you want to do a tower defense this can also be said about Turks/Portuegese but their bonuses for bombard towers only come into play in imp.
Franks/slavs with cheaper castles but they lack bracer.
Bulgarian kreposts are also great.