Do you have a favorite mechanic or subsystem that you port into most or all of the games you run (or play, but this is usually a GM level decision).
For example, I use a 2d20 inspired metacurrency pool in almost every game I run: whatever the currency is, the PCs start with a set pool (maybe based on level or other metric, usually adjusted for the size of the group). Whenever they spend one to do whatever it does, it doesn'd get discarded, but instead goes into the GM metacurrency pool (usually the same thig, but some games makes distinctions). it goes back to the player pool when I use it, and so on.
I have successfully used this with 5E Inspiration, Savage Worlds Bennies, Star Wars d6 Force Points and more.
I find it really improves the fun at the table and enhanced choices around metacurrency.
Do you have a mechanic you like that you import most or all of the time?