In developing Star Crawl for my home campaign (and putting it to paper for eventual release), I've added two statistics: Perception and Credit.
When running and playing DCC, I (and other judges) seem to be inconsistent with how they handle characters noticing things within the current rules. Some use Intelligence, some use Luck; some say Int for seeing and Luck for hearing (and my memory just isn't good enough to be consistent). Perception is a catch all for these. This derived stat is the sum of the ability modifiers for Intelligence and Luck. Some classes (DCC Thief and SC Scoundrel) add their levels to this score.
Credit is a fairly complex stat, and one I'm still working to refine, but the idea is to have a way to simulate the complexities of a modern/futuristic character's financial state without just saying "you have X dollars". Each occupation has a starting Credit Die: major changes in life situation may raise or lower that die, but otherwise it's fairly static. Resource windfalls add a transient bonus to Credit, which will help the character buy stuff now but not necessarily have a permanent impact.
Here's how Credit would work:
Blutark the Particle Harvester has d6 Credit. During his latest adventure, he obtained a frigate loaded with illicit goods. The judge rules that keeping the frigate will increase his credit die (to d8) and selling the cargo will give him a short term bonus (+2). So Blutark heads to the local market with d8+2 Credit for making purchases. There would be a certain threshold for "automatic" purchases (say something with a value less than half your max Credit roll); otherwise, you need to make a Credit roll to afford that item right now. After a month or so, that bonus will be gone but Blutark will still have a d8 Credit die.