Is there any site that has cataloged many of the beasts/monsters used in many webnovels? Either eastern or western beasts.
If were's talking chinese mythology, Wuxiaworld links to this blog: immortalmountain wordpress / glossary / chinese-bestiary And in general either of these will probably be good start. mythus fandom / wiki or tvtropes - IndexOfFictionalCreatures (sorry I have too little posts, so no proper images/links)
Keep in mind you don't have to use any fictional creatures that other people created or use their created version. You as an author have full creative control over your world.