By main I mean only the games that came out for PC:
01. Assassin's Creed
02. Assassin's Creed II
03. Assassin's Creed: Brotherhood
04. Assassin's Creed: Revelations
05. Assassin's Creed III
06. Assassin's Creed III: Liberation
07. Assassin's Creed IV: Black Flag
08. Assassin's Creed Rogue
09. Assassin's Creed Unity
10. Assassin's Creed Syndicate