@C_Chell Here are some tag ideas that I think are relevant to equestria.social's users:

- #mlp
- #mylittlepony
- #mylittleponyg1
- #mylittleponyg2
- #mylittleponyg3
- #mylittleponyg4
- #mylittleponyg5
- #mlpfim
- #mlpg1
- #mlpg2
- #mlpg3
- #mlpg4
- #mlpg5
- #tellyourtale
- #makeyourmark
- #ponies
- #pony
- #brony
- #bronies
- #ponyart
- #ponyartist
- #ponyartists
- #mlpart
- #furry
- #furries
- #furryart
- #art
- #artist
- #commission
- #commissions
- #commissionsopen
- #comms
- #commsopen
- #fanfiction
- #fanfictions
- #fanfic
- #fanfics
- #fimfiction
- #fandom
- #fandoms

Edit - some more:
- #mlpmusic
- #ponymusic
- #horsemusic

Edit 2 - even more:
- #mlptyt
- #mlpmym
- #mlptellyourtale
- #mlpmakeyourmark