Depends on what you mean by strong cultbase
If you are talking about how brainwashed and cucked they are, probably cuckbeats and cumsharts since anyone who isn't has already dropped them.
Fancucks beat even those two if you still want to count them though
In terms of online representation compared to numbers, KFP and Takos
In terms of total representation, Takos.
Like jesus christ, that reddit oshi flair ranking is insane. Ina also wins virtually ever youtube poll