These are general rules which can be used individually or in combination to spice up some games, typically 7-Card Stud.
Each player gets to pick their own wild card before the hand is dealt. It is only wild for that player.
Each player gets to pick a Death card for the player to the left, right, or both. If that player gets that card (typically face up only), the player must drop the hand immediately. On each succeeding round, the Death cards are reassigned - that is, if the player to your left dies because of your Death card in round one, the next player to your left can be killed from your Death card in a succeeding round - the Death card of the now dead player has no effect on subsequent rounds.
Each player gets to pick their own Death card. If that player gets that card (typically face up only), the player must drop the hand immediately.
If a player gets a designated card (typically a Joker), then that player passes it immediately to another player, typically predefined to be the player to their left or right. That person must drop their hand immediately.
You can combine two or more of the above. For instance, in Happy Murder, a player's chosen wild card is the Death card to the adjoining players.
We typically play Happy Murder Manslaughter, which is defined in the Seven-Card Stud section.