I've finally decided to give the DM's Guild a try. My first effort is the Folio of Fiends, which takes a bunch of classic monsters from the Fiend Folio from the early 1980's and updates them to D&D 5e. It's pay what you want, so if you don't want to pay anything, you're in luck!
Go check it out: Folio of Fiends
Thank ya kindly.