Mostly Unfinished freeware space combat (with some trading, maybe)games that showed potential-
Epiar (has potential, but floaty and has balance issues)
Transcendence (and maybe Frontier;Not-so-frequent updates, campaign unfinished)
Naev (been awhile since " 0.6.0 following in the not-so-distant future", still no 0.60; team maybe losing steam[no pun intended])
ASCII Sector (maybe dead project)
Space Exploration: Serpens Sector (Dev sort of went hiding, either stealth development or abandoned project; "I want to remain kind of stealthy for now, and only give a firm date on release when I have on my computer a beta version of the game, ready to be released save some typos and minor bug-fixes.
It will be done when it's done. And it will be.")
Forever Eden (guy lost his 3d graphics man, my have abandoned project)
Darkverse (has said he intends on finishing it, but it's been awhile)
Starflight:The Lost Colony (Slow game, door sounds are atrocious, only1/2 finished games on the list)
Also, 3030 Deathwar became free, but other than a modded version (where I can't seem to land on stations) I found on the (Old) SpaceSimCentral Forums, I couldn't find it. seems the new site fixed up the links, though the clg mod still won't work right for me and DLing requires an account.