Space trading games

Spacezero is a 2D space builder. GPL3. Net gaming to 8 players.

http://spacezero.sourceforge.net/

I haven't tried this one but it would seem to fit the bill https://libregamewiki.org/Naev

I'm not familiar with any of those games you mentioned, but how about Naev?[0] It's actually in a very incomplete state and in desperate need of some love (for the best experience, stick to the Empire; lots of dead-ends exist with everyone else), but it's a game that sort of comes to mind when you say "space trading game" (it's more mission-oriented and most missions are delivering cargo, but anyway...)

Another one that looks interesting to me at least, though it's 3-D, is Pioneer.[1] This one seems to be in active development, unlike Naev (most recent release was in August).

[0] http://blog.naev.org/
[1] http://pioneerspacesim.net/

I've tried SpaceZero a little bit and it's easy since it's already in the Trisquel repos. It seemed interesting and might fit the bill.

I have no idea about Oolite because the 3D graphics were too buggy, but that's probably the fault of my Nvidia graphics card. Sounds good, though!

The other suggestions here sound promising. Thanks all and cmhobbs for starting this topic.