Hi there! so i'm an indie and most work is done by myself, i only bought a music pack and sounds pack on the asset store and hired some freelancer artists for some graphics, i'm not sure how those should appear in the credits. I also did some graphics and sound editing but i don't think i have to repear me name on every category? Some say "hired or bought" stuff should go into the "special thanks" section. So i'm a bit confused that's what i have right now: Game by Me Art/Graphics ? Sound/Music ? Beta testers ... Special thanks ...
Almost every pack will have some sort of attribution information in the accompanying license file, if they require it at all. Otherwise do what Mauri said.
Sounds good, they don't need attribution after purchase you own all rights, but what @Mauri said sounds good