If you go back to about 1995 / 1996 / 1997 then Hartlepool had.

Bristol RE
Bristol LH
Bristol VR
Leyland Olympian
Volvo Olympian
Leyland Lynx MK 1
Leyland Lynx MK 2
Leyland National MK 1
Leyland National MK2
Wadham Stringer Dennis Falcon
Northern Counties Dennis Falcon
MCW Metrobus
Optate Delta
Volvo B10
Optare Metro rider
Fleetlines

Quite an impressive list really.