Here's my tag directory for the specific tags, but I generally use the following tag categories on every profile:
▶︎ Body type. Are they humanoid, anthro, or feral?
▶︎ Species. More specific species, excluding ethnicity.
▶︎ Ethnicity. Most applicable for my demons, since those are most numerous. Also includes if they're pureblooded.
▶︎ Gender and sexuality.
▶︎ Age group, like toddler, young adult, elder, ancient, etc. all relative to their species
▶︎ Faction.
▶︎ Time period. Either modern or past.
▶︎ Favouritism. Tags such as fav character, fav design, if I want art, and my personas.
▶︎ Completion. From complete all the way to badly needs rewrite.
▶︎ Detail. From highly detailed to empty.
In the end my profiles end up having a ton of tags, which is an unfortunate side effect of having as many tags as this, but I like browsing in my tags! If I could hide tags, I would tag so many more things like eye colour, skin colour, hairstyle, etc. just to play around with, but no one wants a 20 scroll ling tag section to look at c':