My favorite part of Space Aces is that it's fun to add expansion modules since every module fits on a business card. So far... this is the list I have. And it's growing daily ha. Let me know if you have any ideas!
Hyperspace Hubris (space travel encounter and sector crawl generator)
That One Where... (B-Plot Generator)
The Trouble With Stasis Pods (starter scenario)
Stellar Colossus (Mega Ship threat contributed by DiscoSoup)
Spacecar 500 (spaceship racing!)
Mirror Universe (it's fun to be the bad guy and wear a goatee, also 1's are good & 20's are bad)
Lazerball (like sports but with lasers)
Galaxy Food Truckers (get a good review on Space Yelp)
Starbase Epsilon (base builder)
*Names are subject to change.