Every gaming group has their own style of gaming and their own rules they use at the table. Here are some of ours:
In addition to getting a d6 for a Raise on attack rolls we wanted something to give Wild Cards (both PCs and NPCs) a bit more kick. When both Fighting and Wild Die Ace on an attack roll you double the total damage. This includes the bonus d6 if you hit with a Raise.
If a Wild Card rolls double one's on an attack roll they may not spend a benny to re-roll. In addition, the GM still gets to "make up something rotten to happen to your character". This only applies to combat. Bennies may still be spent to reroll critically failed Skill attempts.
Critical Miss Benny
If a Wild Card rolls double one's on an attack roll they gain a benny. This helps off-set the "rotten" thing that is about to happen to your character! Remember, this benny cannot be spent to re-roll the miss.
Bennies for XP
The number of bennies in-hand at the end of a play session is the chance on a single d6 to gain one extra experience point. A player with six or more bennies can divide them as desired between two d6 rolls for one XP each. Two rolls is the maximum. (Adapted from Advanced Dungeons and Savages)
Any player may nominate another player to earn a benny for a witty comment, good roleplaying or any other "in-game" reason. The other players then vote yea or nay. A player may only earn one "voted" benny per play session.
Benny for Re-Shuffling
The GM may give the action deck to the player with the least amount of bennies at the table to reshuffle the deck. They earn a benny. (Adapted from Evil Mike, who adapted it from Clint Black)