Annie Sawyer: A very insecure ghost with abilities that are usually controlled by her emotions. Telekinesis, teleportation, and intangibility.

Chell: Test Subject. Wields Portal Gun. Equipped with Long Fall Boots (able to fall from any height). Immune to serious brain damage, laws of physics. Never gives up.

I'm only being half serious about one of these.

 

Henry Foss: Geek, computer scientist and weapons designer. Capable at maintain defenses and issues that arise. Class nine-hyper-accelerated protean life form, aka werewolf.

 

Gene: Genetically similar to human, useful for experimentation to simulate effects on human. Enjoys watching SpongeBob Squarepants, and take-out Chinese.

Here's another one:

Kenzi: Known aliases, Shaman Czigany, Meow Meow, Kenzi Williams, Kenzi McAdams, Kenzi Rogers, Rhino Levine, Ninotchka Alexandrovich, Toni Soprano. Quick-witted, sarcastic, and reluctant to trust others, Kenzi is a gifted con artist, thief, with the street-smarts to match. Speaks fluent Russian and is a master of disguise and accents for infiltration. Survivor, professional thief, and basic sword training.