Everyone with Oprah in their names (Save-Me-Oprah, Shave-Me-Oprah and OprahIsBlack)
iHypeMusic and MiMiLamb (both Mariah stans)
Latch & Lethal
MG2K & Toya (don't why that is, though.)
Callisto (formerly iBeyonce, I think) & Flare (I remember Callisto had Flare's current avi at one point)
primo & chilluminati
Rem & Lem (aren't they cousins?)
Rihyonce & Elliot
I used to get Cap10 Planet and CaptainMusic confused because of their names, but they're pretty distinct personalities who stan for different artists, so that confusion didn't last long.