Old characters unknown artists?..

I’ve got lots of characters and some aren’t getting any loving, But the thing is some of them don’t have any credits from the designers on them and/or the players no longer are on equiverse
Im just wondering if it’s still okay for me to sell them or not.
Ps I brought them years ago so I can’t remember who did them either 

If you post the characters, artists the design belonged to will speak up or may know the artist. Some people have their own specific style that is recognizable. If no one claims to know them I think it's okay to sell them, but I'm not positive on that part. I've been here since 2008 though so I may or may not be able to help lol.