This app was mentioned in 4 comments, with an average of 2.50 upvotes
Fantasy Insult Generator is my favorite app for this. Use it every session.
https://play.google.com/store/apps/details?id=com.ixiestudios.fantasyinsults
"Sandy-trousered shit-kicker" "Shrill heavy fraud"
It adds a lot of flavor and it's more fun than just saying "Hey you! You suck!"
> Ring of Vile Mockery