oHHH i was really tempted to say like... Furbies or Littlest Pet Shop or something, but I don't know if those would really count as fandoms, also they're like... super different from Spooki Boo... so it won't work unfortunately...
But, I'm gonna say something along the lines of an older anime instead. I'm leaning a bit towards Dragon Ball Z, as the icon reminds me of that art style fsr, but I also think just about any, like... unorthodox magical girl anime would fit. I'd name one, but I don't watch a whole lot of anime sadly :'V