Until this wiki creates an article, I decided to see what people found from their D20 rolls in Tiny Tina's Assault on Dragon Keep. Because reasons. Dice Chests and Slot Machines, just throw whatever your rolls were here.
Here's mine. Not a lot because I have an awful memory, but a start :B
1 = 1 Eridium bar and a live grenade.
20 = Fireworks + Legendary (according to this video). IceSk8 0750h, Nov 17, 2015 (GMT+8)
18 = 3 Seraph Crystals
8 & 9 = Free Spins
(psst imma take a wild guess and assume rolling 20 on a slot machine grants a legendary)
Double 20s on a chest got me a Shock Infinity. Victyko