The first one I played was Brotherhood. And I was hooked! I think I've completed it 4-5 times 😅. I also played Assassin's Creed 1, 2 and 3 and Blag Flag. I played Origins on a friends account but never finished it.. and the Assassin's Creed Chronicles: China.
I was a big fan of the games, I still want to read the books!
oh wow looks like you stopped after you've played the best one! Black Flag is still apparently the best. I've yet to try it