twilight sparkle = yugi (main protagonist)
 
alicorn twilight = yami yugi (superpowered version of main protagonist)
 
rainbow dash = joey (obvious casting/i’m not very good at explaining too deep :)
 
fluttershy = tea (peaceful, yet kleptomaniac)
 
pinkie pie = tristan (random)
 
rarity = mai (same reason as rainbow dash = joey…)
 
trixie = seto (main protagonist’s rival)
 
silver spoon = mokuba (just seemed to click with me :)
 
princess luna = marik (heroes turned to dark side and back again)
 
nightmare moon = melvin (because evil version of marik)
 
snips & snails = rex & weevil (this one’s obvious…)
 
diamond tiara = noah (this one’s also obvious… also because rape face…)
 
jet set = gozaburo (because filthy rich was too nice for the role…)
 
roid rage = hobson (another obvious one…)