Based on stans that you know and true famous stans (stans irl not for publicity)

I think Britney

I mean we have Adel (she is a Stan,she even canceled her own show)

Carlie XCX she knows every Britney song by heart

Chloe M she stayed up for WB release
Lana
Marina and the diamonds she has canceled her show for Britney

I'll update my list imo.