My top three most favorite t rated games are Lara croft legend, shenmue 2, and jet set radio future.
You could play GunZ Online, it is a Matrix-esque shooter. The site for the game can be found here: at link below
Battlefield: Bad Company or Mercenaries 2 I have played both of them and they are pretty awesome! HOPE THIS HELPS
That could be MAG for online players, which is rated T and considered a first person shooter. GRAW 2 or Ghost Recon Advanced Warrior 2 is considered a great Tactical shooter and is also rated T. Warhawk is another kind of shooter also rated T and centered on aerial combat, ground vehicle assaults, and infantry offensives.
Some of the Portables have t rated versions of game like Call of Duty Black Ops on Nintendo DS
Halo Wars is rated T for teen because the game does not have much violence like the regular first person shooter game. There is also rarely any cussing in the game. Though the game has a lot action in it, it can be related to Star Wars: Empire at War.
if your looking for a shooter game then battlefield bad company 2, call of duty 3, and medal of honor airborn
Good game kid friendly
Call of Duty 3 is a good Teen (ESRB) rated first-person shooter for PlayStation 3, PlayStation 2, Xbox 360, Xbox and Wii. Battlefield 2142 is a critically acclaimed Teen rated first-person shooter for Windows PC and Mac OS X.
SOCOM Fireteam Bravo 2
A first person shooter video game, WW2 based game, and a very well seller in its time. It is an old game, comparing call of duty 7 is out now. Reasonably good graphics, good story, and is rated T for teen, unlike it's more recent relatives which are rated M. Since it is 2012, hte game should be cheap. $3-$10 range. Hope I helped!
Okay so to answer your question I just did a search on the ESRB website. I found Brink, although I can't vouch for how good it is, I have never played it. You can also get Battle: Los Angeles. I'm sure there are others as well, but finding a T rated shooter is not an easy task.
It is rated T for teen.