I have really only worked FOR one paintball company (apart from my own, Simonized LLC), which was NPS and then became KEE.
I have worked with, or almost done deals with,
AGD
Planet Eclipse (almost went into business with them making loaders)
Angel (when it fell through with PE I was talking to Angel about it before NPS swooped in and signed me up)
NPS
KEE
While working for NPS I worked with many companies they owned or partnered with.
Off the top of my head that would be
Bob Long,
ICD,
Race,
PBX,
Hater (LTD loader boards in the Vici line)
And that doesn't cover the brands which some people think of as separate but are actually owned by the companies mentioned above.
Things like
BT
Empire
Invert
Halo
JT
Extreme Rage
32 Degrees
Vents
As for the list of products... that's going to take a while.
Almost, but not quite anything hards good related, that's come out of NPS since 2004 was either my design, or designed by the team that I direct.