Legs and Torso bits, what's out there?

I have all these guns and arms left over from my boyz and loota/burna kits.

Seems like it would be cost effective to just buy legs/torso/heads and use the rest of the kit instead of buying brand new boxes.

So far I've heard of FoxBox, wargaming exclusive, and spell crow.

Are there any other legs and torso bits that fit GW arms well?

Do most of you look for GW bits on Ebay in instead of third party bits?

Just trying to make the most out of the boxes since this is my first full sized army.

Thanks in advance!