dice superstitions, yeap my group has it.
Personally I have about 6 complete sets with around 25d6 extra for the big rolls. I have 2 d20's that I use exclusively when I play (very very rarely) and DM. My primary one is a metallic blue with white numbers that I have had for over 12 years....referred to as "Metallic"... and the players hate that one. If you just test roll it, it rolls random, but when the rolling in game against the players this die loves the 18+. I've lost count the number of times it has rolled 3 or more 20's back to back in front of the players. I've had them threaten it with a hammer before when the BBEG is slicing up their characters.
The other die is a black and gold d20 referred to as "Black Death" and it lives up to it's name. I don't use it much but when I do characters start dropping, as it matches Metallic almost exactly in the way it rolls. The other 4 sets of dice I loan out if need be, but no one uses my 2 sets and they know not to touch them.
My wife, a new gamer that started almost 4 years ago when we were dating, has a set and she is much more into the superstition, she has even jumped up and caught her dice in mid-air when another grabbed it and rolled it cause they didn't want to dig out their dice just yet. That was pretty funny both in her reaction time and the other player's face at her doing that.
The other players in the group have the same kind of setup with favorite dice but a few are not so attached to them. I even seen one player set his d20 up on a window ledge overlooking the gaming table after it rolled too many 1's to punish it while he took to using his back up set.
The dice superstitions are alive and well in my group!
RD