If you're looking for self-contained graphic novels, you absolutely can't go wrong with "Saga" by Brian K. Vaughan and Fiona Staples. It's such a brilliant blend of fantasy and sci-fi with amazing characters and incredible artwork! The first volume kicks everything off beautifully and has a gripping narrative that doesn't rely on prior knowledge of anything else.
Another fantastic choice is "Maus" by Art Spiegelman, which tells a powerful story through the lens of graphic storytelling. It's profound and haunting, yet it's totally engaging.
If you want something a bit lighter, check out "Scott Pilgrim's Precious Little Life" by Bryan Lee O'Malley. It's a fun, quirky story filled with video game references and a unique art style.
What kind of genres are you leaning towards? That might help narrow it down a bit!