A Couple of Other Old House Rules I've played under

From the memory bank

#1 20 and confirm. My first experience with something like the D20 crit system, came way back in 1997. One of our local Grogs - D. Balrog used a system that was Roll and 20 and confirm and you get double damage. How that rule filtered into 3x I'll never know.

#2 Read and Detect Magic as at will abilities. This was back in the early 2e days and in my limited experience in a fighter heavy (7 fighters and a mage!) it worked just fine.