Well, GTA wouldn't be GTA without the vehicles. 
So here's a list of the vehicles that are on GTA3.
Cars:
Banshee
BF Injection
Blista
Bobcat
Borgine
Bus
Cabbie
Cartel Cruiser
Cheetah
Coach
Diablo Stallion
Esperanto
Flatbed
Idaho
Mafia Sentenial
Mr.Whoopee
Mr.Wongs
Kuruma
Landstalker


Emergency:
Ambulance
Barracks
FBI Car
Firetruck


Plane:
Dodo
Limo
Linerunner
Manana
Moonbeam
Mule
Patriot
Perrenial
Pony
Rumpo
Securicar
Sentenial
Stretch
Stallion
Stinger
Taxi Cab
Triad Fish Van
Yakuza Stinger
Yankee
Yardie Lobo
Police Car
SWAT Van
Tank - Rhino
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