Wrestler is a code name AMD/ATI gave to that model. I found this wikipedia article that has loads of names.
fxglr is a display driver so a piece of software to drive your videocard. So something different ;)
fglrx is the name of the Linux display driver used for ATI Radeon and ATI FireGL family of video adapters and stands for "FireGL and Radeon for X". It contains both free and open-source and proprietary parts. Starting from Catalyst 7.11, the ATI Proprietary Linux driver was renamed ATI Catalyst Linux.
So one (wrestler) is the name of a piece of hardware that the other one (fglrx) can use to use your display.
VESA is an organisation (Video Electronics Standards Association) and they define and create standards as their name implies.