From the wiki: Tagged for posts that cannot be considered even remotely furry.

Do not use if the post contains a mix of furry and non-furry characters.

• human characters are the most obvious.
• humanized characters that would normally be considered furry, such as those from Equestria Girls
• humanoid races such as elf, orc, troll, goblin, gargoyle, ogre, and gnome
• human-like aliens, angels, demons, monsters
• mechanical characters such as robots (android, mecha, etc.)
• golems, plants, goo creatures, tentacles (particularly when they are only interacting with human characters)
• zero pictured - A pretty landscape, a toaster, a car.

Furry:

• anthro, feral, centaur, minotaur, naga, scalie
• animal humanoid (kemonomimi) - Humanoids with minor animal characteristics. This includes some monster girls, such as harpies.
• chimera if they have animal parts.
• photomorph of real-life humans into furry is considered furry (note that real photos are generally discouraged)
• robots and animatronics that are modeled to look like feral or anthro animals.