Tribes Armpatches by Rifter@planetstarsiege.com (http://www.planetstarsiege.com)
In addition to the Tribes Armpatches, there is one of Dust Puppy, of User Friendly fame (http://www.userfriendly.org).

Any updates will be posted to http://www.planetrainbowsix.com/

Rainbow Six Database has a great tutorial on creating arm patches and how to install them.  Here is the tutorial:http://rsdatabase.gamenation.com/armpatchtut.shtml

There are an additional 24 patches that do not fall in the above catagories.  They are from Half-Life Decals. 
I found these cool decals at http://www.planethalflife.com/logos/, and converted them to Rogue Spear armpatches.