While I have done elaborate d100 tables for everything I sometimes like a simple quick d12 table even just to set a mood. Sometimes you just need a quick result in game. These tables are to provide a quick mood compared to my larger ones. Considered including stats but this gets to be a problem with high level monsters with more abilities.
The first table results are more likely to be scenic than fights but could be opportunities for rumours, meeting new people. On a common encounter table roll on a 12 you can accept the result or roll a second d12 for uncommon encounters. You could also use the uncommon tables at night or when evil omens are out. Or roll on my equivalent d100
Here is a link
https://drive.google.com/open?id=1s7mL67xeV8722sZWppx17eZ4w8G4jTJy
Possibly do a psychon one by terrain or one based on my dungeon zones