Depends what kind of stuff you like most. There's the American Punk Rock scene which had some great bands like Black Flag, Bad Brains, Bad Religion, Rancid, Minor Threat etc.
If you like the Sex Pistols and Clash you might wanna search for some British punk bands like Cock Sparrer, Sham 69, Angelic Upstarts, Cockney Rejects
The newer 90s stuff that is more pop/ska is still really good. NoFX and Rancid are two bands you cant go wrong with, they're some of the most well known bands that have transitioned from the 80's punk era into modern stuff, so they have a huge discography that covers most sounds and styles of american punk rock. Guttermouth, Pennywise, Lagwagon, Propagandhi, Refused, old Rise Against...
Punk is really broad because it incorporates a lot of other sub genres like ska and metal. If you pick out a specific band or style you like I could probably recommend some bands. XD