Under standard Savage Worlds rules, there are two types of characters. There are Wild Cards, who are like the player-characters: they get to roll a Wild Die with skill checks, they get Bennies of their own, and they can take three Wounds before becoming Incapacitated or Dead on the fourth Wound. Then, there are the Extras, who are like everyone else: they do NOT to roll a Wild Die with skill checks, and they can become Incapacitated or Dead on their first Wound, not their fourth. At first, that was enough, but over the years, some GMs have found a need to have more variance in their NPCs. Publishers came to the rescue, and now there are at least five character types: Extra, Wild Card, Henchman, Joker and Mook.
Henchmen are found in certain settings (such as Slipstream), and are very popular with Triple Ace Games products. Henchmen are Extras that can take three Wounds before becoming Incapacitated or Dead on the fourth Wound. They do not receive Bennies of their own (unless they are Lucky), nor do they get to roll a Wild Die with skill checks. Henchmen are generally great to use for the Big Bad Guy's lieutenants in a particular scene, as they have some staying power, but otherwise are just like the Extras that the players have come to know and love (or hate, as the case may be.)
I can't remember where I first saw the concept of the Joker NPC, but I tend to prefer them to Henchmen in my non-combat oriented "second tier" NPCs. Jokers are Extras that get to roll a Wild Die with skill checks. They do not receive Bennies of their own (unless they are Lucky), and they can become Incapacitated or Dead on their first Wound. Jokers are generally great to use for highly skilled specialists that still go down easily in a fight. This could include frail mages, a doctor or healer, or a sagely scholar. When you as a GM want the NPC to succeed more readily, without raising their skill die dramatically or making the NPC extra tough, then Joker is the best bet for you.
Finally, the concept of Mooks was introduced in Savage Mars, and fills a roll similar to Minions in 4E. Mooks are essentially Extras that become Incapacitated or Dead when they are Shaken. They do not receive Bennies of their own (unless they are Lucky, but then again, they are Mooks, so that isn't likely), nor do they get to roll a Wild Die with skill checks. These guys are basically fodder for your player-characters to wade through, so you can have that massive fight of a few men against hordes and hordes of creatures, until they find themselves standing before the Big Bad Evil Guy for a final showdown.
Table: NPC Types
|NPC Type||Wild Die||Bennies||Incapacitated/Dead|
|Wild Cards||YES||YES||On 4th Wound|
|Henchmen||NO||NO||On 4th Wound|
|Jokers||YES||NO||On 1st Wound|
|Extras||NO||NO||On 1st Wound|
Personally, I'm not likely to use Mooks very often, but I'm more than willing to use Jokers and Henchmen to supplement my Extras. Too many Wild Cards creates a higher potential for character deaths and potential TPKs. These allow me more creative freedom, while varying the challenge of a given scene. What do you think?