Pretty much everyting from Will Eisner besides his The Spirit series (a great series)
Pyongyang: A Journey in North Korea (his other books are also quite enjoyable)
Habibi
Everything from Jiro Taniguchi
Goddamn this war! by Tardi (and also It Was War of the Trenches)
Virgil
Daytripper
Sci-Fi:
Saga
Akira
The Keepers of Maser
Druuna
Star Wars: Knights Of The Old Republic (50+5 issues) easy accessible
Adventure:
The Witcher: Fox Children + House of Glass
Corto Maltese (every issue is mostly self-contained with some small references to happenings and characters)
Corto Maltese: Ballad of the Salt Sea
I also have a lot of other European comics if you want