- Hear Noise (pages B8, B21, X6): Anyone has a 1 in 6 chance, demi-humans have a 2 in 6 chance, thieves start at 2 in 6 and improve to 5 in 6 by level 11.
- Expert Miner (page B9): Dwarves detect slanting passages, traps, shifting walls, and new construction with a 2 in 6 chance.
- Secret Doors (pages B9, B21): Anyone has a 1 in 6 chance to find a secret door, elves have a 2 in 6 chance.
- Hiding (page B10): Halflings have a 2 in 6 chance of staying undetected in dungeons.
- Opening Doors (page B21): Anyone has a 2 in 6 chance of opening a stuck door, strength modifier applies.
- Finding Traps (pages B9, B22): Anyone has 1 in 6 chance to find a (non-magical) trap, dwarves have a 2 in 6 chance.
- Lighting Fires (page X10): Anyone has a 2 in 6 chance of lighting a torch/fire with a tinderbox in one round.
- Foraging/Hunting (page X51): There is a 1 in 6 chance of finding enough food (or encountering a suitable animal to kill) per day.
I left out d6 rolls that are not usually thought of as "skills", for example the "springing a trap" roll, random encounters, surprise/initiative/pursuit, stocking dungeons, etc. Did I miss another player-facing "skill" use of the d6? Please let me know if I did, I hope this will be the definite post on the subject in the years to come. :-)