can someone tell me what other marvel characters appear in this film?

Mintberry Crunch!

The Klaw is in it,and Bucky in a post credit scene.

Other than the Wakandians and those seen in the clips and trailers (such as Klaw) [spoiler] Bucky Barnes is the only notable Marvel character to appear, he shows up [/spoiler] in the post-credits scene. It’s a wonderful cameo and a small preview of what’s to come. Oh, and good ol’ Stan Lee as always.

No other established MCU character had much of a reason to appear in Black Panther.

I think Ant-Man was in one scene but you have to look really closely to see him.