One of the things I really like about the Glass Cannon Podcast is the the GM’s use of “bottle caps” [**Link leads to spoilers**] – virtual tokens handed out to the players who do something exceptional during play. It could be for outstanding role playing, a clever solution to a problem or even making the group laugh. A player can exchange the token for a second roll of the die, letting him take the higher of the two rolls.
5e has a similar rule, proffered by the Advantage mechanism. From the 5e SRD:
“Sometimes a special ability or spell tells you that you have advantage or disadvantage on an ability check, a saving throw, or an attack roll. When that happens, you roll a second d20 when you make the roll. Use the higher of the two rolls if you have advantage, and use the lower roll if you have disadvantage. For example, if you have disadvantage and roll a 17 and a 5, you use the 5. If you instead have advantage and roll those numbers, you use the 17”
We’re going to do something similar for Knotted Oak campaign – exception game play (in whatever form it occurs) will earn the player a bottle cap they can hand in for some help with a single die roll.