Configs (CFG)
Configs refer to the configuration files which are used by the game to quickly change game parameters, such as graphics options. Many configs are designed to improve game performance through lowering graphics settings, as well as providing extra functionality through use of client commands, such as viewmodel_fov and interp settings.
FPS Configs
FPS configs strive to lower game graphics as much as possible in order to increase the framerate (FPS) of the game. Popular graphics configs include Chris's Highframes, Maxframes, and Dx9frames, while configs such as m0reframes have been used in the past.
TF2Mate - TF2Mate is the most popular config generator amongst the TF2 community. It allows players to configure their graphics settings, binds, and also comes with a crosshair switcher that allows the user to pick their own crosshair for each weapon slot on each class.