Linked from
The 23 pages that link to Finite group, each with the reason it gives.
Burnside's lemmaNarrower topic: The averaging formula sums over a finite set of symmetries.
Monster groupNarrower topic: The Monster is an exceptionally large example of a finite group.
Brauer–Suzuki theoremNarrower topic: Finiteness is an essential hypothesis of the theorem.
Frattini's argumentNarrower topic: The argument concerns finite groups, where Sylow subgroups exist.