Transformers: Beast Wars

Rhinox  (Voiced by Richard Newman)
Rhinox serves as a Maximal scientist and doctor
Alt Mode: Rhinoceros






Cheetor  (Voiced by Ian James Corlett)
Cheetor is the youngest member of the Maximals and acts as a scout
Alt Mode: Cheetah







Rattrap  (Voiced by Scott McNeil, Kappei Yamaguchi)
Rattrap is a Maximal specializing in espionage
Alt Mode: Rat







Dinobot  (Voiced by Scott McNeil, Keiji Fujiwara)
Dinobot is an ex-Predacon turned Maximal, he is the groups strongest warrior
Alt Mode: Velociraptor







Tigatron  (Voiced by Blu Mankuma)
Tigatron was the first protoform to land on Earth, he prefers living in the wild
Alt Mode: White Tiger

Airazor  (Voiced by Pauline Newstone)
Airazor is a female Maximal who transforms into a hawk, she specializes in long range recon.
Alt Mode: Chicken Hawk

Silverbolt  (Voiced by Scott McNeil, Mitsuo Iwata)
Silverbolt was at first a Predacon, but switched sides rather quickly. He is a fuzor, and has the characteristics of two separate beast modes merged into one.
Alt Mode: Wolf/Eagle

Depth Charge  (Voiced by David Sobolov)
Depth Charge is a Maximal with a grudge against Rampage, he specializes in undersea combat, tracking, and firearms.
Alt Mode: Hammerhead Shark

Tigerhawk (Voiced by  Blu Mankuma, Koichi Tochika)
 Tigerhawk was created by The Vok to act as their Earthly emissary, he/she is the result of the bodies and sparks of Tigatron and Airazor being fused together.

Optimal Optimus  (Voiced by Garry Chalk)
Optimal Optimus was the short lived fusion of Optimus Primal and Optimus Prime.

Predacons

Megatron  (Voiced by David Kaye)
Megatron is the leader of a group of Predacons who stole the Golden Disc on Cybertron. Megatron, along with the Predacons who escaped the theft fled aboard the Darksyde, travelling through a rift in time and space to primitive Earth. 
Alt Modes: Tyrannosaurus Rex, Dragon

Terrorsaur  (Voiced by Doug Parker)
Terrorsaur is the scheming Predacon who wishes to take command of the Predacons, but after seeing first hand what happened to Dinobot, he is cautious to hide his ambitions,
Alt Mode: Pterosaur

Tarantulas  (Voiced by Alec Willows) 
Tarantulas is the mad scientist member of the Predacons, much like Terrorsaur he also schemes to seize control of the Predacons, he is somewhat obsessed with securing protoforms and making sure they select an arachnid as their alt mode.
Alt Mode: Tarantula

Waspinator  (Voiced by Scott McNeil)
Waspinator is....Crazy. He is usually loyal to Megatron, but much like most of the other Predacons, has turned on his leader at one point. Waspinator refers to himself in the third person at all times.
Alt Mode: Wasp

Scorponok  (Voiced by Don Brown)
Scorponok is the only Predacon truly loyal to Megatron, he is also the dumbest member of the group. He has been called the second in command of the team, but clearly that title is only given to him for his unwavering loyalty.
Alt Mode: Scorpion

Blackarachnia  (Voiced by Venus Terzo) Blackarachnia was the first protoform recovered by the Predacons, Tarantulas made sure to give her a spider alt mode. She is prone towards scheming and backstabbing, but ultimately defects to the Maximals.
Alt Mode: Black Widow Spider

Inferno  (Voiced by Jim Byrnes)
Inferno makes Waspinator look sane. He was the 2nd Maximal protoform to be reprogrammed into a Predacon, and has a mentality mirroring his beast mode.
Alt Mode: Fire Ant

Quickstrike  (Voiced by Colin Murdoch)
Quickstrike is the cowboy like Predacon fuzor, he's quick to shoot first and never ask questions.
Alt Mode: Rattlesnake/Scorpion

Rampage  (Voiced by Campbell Lane)
Rampage is a true psychopath, he is the result of a Maximal experiment to artificially duplicate Starscream's immortal spark. It is revealed that the Avalon's crews true mission was to dispose of Rampage in the deepest regions of space prior to being sidetracked by having to pursue the Darksyde. Alt Modes: Crab/Tank

Ravage  (Voiced by Lee Tocker)
Ravage travelled back in time with the purpose of altering history so the Decepticons would win the war. He planned to achieve this by destroying the Autobots while they were still in stasis.
Alt Modes: Panther/Cassette

Dinobot II  (Voiced by Scott McNeil) 
Dinobot II was created by Megatron in an effort to replace the deceased Dinobot, and create a new worthy second in command. Dinobot II was cloned from Dinobot, and given life by a portion of Rampage's spark. He strangely seems to have flashbacks of the originals memories.
Alt Mode: Cybernetic Velociraptor

Autobots

Optimus Prime  (Voiced by

Bumblebee  (Voiced by

Prowl  (Voiced by

Jazz  (Voiced by

Ironhide  (Voiced by

Ratchet  (Voiced by

Decepticons

Megatron  (Voiced by (Garry Chalk)

Starscream  (Voiced by Doug Parker)

Soundwave  (Voiced by

Skywarp  (Voiced by

Thundercracker  (Voiced by

Protohumans

Leader Neanderthal  (Voiced by Garry Chalk)

Chak  (No voice/uncredited)

Una  (Voiced by Susan Blu)

Others

Clone-1  (Voiced by Scott McNeil)

Transmutate  (Susan Blu, Haruna Ikezawa)

Unicron (hologram)   (Voiced by

Snowstalker (No voice/uncredited)

The Vok  (Voiced by Blu Mankuma/Richard Newman, )

Cyber-Raptors (No voice/uncredited)