First released in 1980, The Rogues Gallery remains one of my most beloved AD&D products. I got a heck of a lot of use of it back in the day, which, on reflection, is an odd thing. One of the many ways in which I feel older editions of D&D are superior to their putative descendants is the ease with which characters, even high-level ones, can be created. Only spellcasters require any time at all and even they don't take more than a few minutes to stat up. So why did I find The Rogues Gallery, which is primarily just a collection of pre-generated characters so useful?
Thinking about it now, there are two answers that spring immediately to mind. The first is that, in 1980, no one I knew had their own personal computer. Creating NPCs had to be done by hand and, even if each individual character didn't take very long to generate, generating dozens of them could still take up some time. The second answer is a sub-set of the first: when generating PCs by hand I often found it all too easy to fudge the results. For whatever reason, I tend to be easier on NPCs than I am on the PCs in my campaigns when it comes to rolling ability scores. Having a pregenerated list took this unfortunate tendency of mine out of the equation and ensured that there were clerics with 10 Wisdom and fighters with 6 Dexterity kicking around, often as hirelings or henchmen. And of course, products such as this are a godsend if your players are keen to employ hired help, as mine almost always did.
The Rogues Gallery was also interesting for its collection of "Personalities," the characters of the TSR staff and their friends and family. This is where we first get to see the stats of Mordenkainen and Tenser, Robilar and Bibgy. This is cool in its own right -- who didn't want to know what Gary Gygax's characters were like? -- but also because it gave us a glimpse into D&D as it was played by the people who knew it best. What's obvious is that Neutral and Evil characters were much more common than I'd assumed at the time (though that makes perfect sense to me now). Likewise, there was quite a diversity of character types, though fighters and magic-users predominated, as one would reasonably expect. Magic items were comparatively rare, with only the most potent of the characters included in the book having more than a handful of them. I know that there are direct statements from Gary and others that the depictions in The Rogues Gallery are fanciful and under-powered compared to the real characters, but, as an example of what TSR in 1980 wanted to present to players, it's instructive nonetheless. I'll also note that many of the characters included here have stats that suggest either egregious fudging or many increases through the use of magic and magic items.
The Rogues Gallery is notable for being a rare example of a product released under the name of Brian Blume. As I've stated before, I think Blume gets unfairly singled out as the source of everything that was rotten in TSR, a view that simultaneously gives the man too much and too little credit for his role in the history of the early hobby. I find it odd that he's the author of both this supplement I loved and my favorite OD&D supplement. I have no idea what that says about him or me, but it's noteworthy nonetheless.
There are a couple of free products out there that fill a similar niche to The Rogues Gallery. The first is Kellri's Old School Encounters Reference, which is, quite simply, one of the best D&D resources ever compiled. The other is Garish's 140 Henchmen for Hire, which I've used extensively for my Dwimmermount campaign. I recommend both highly.
Finally, The Rogues Gallery contains some terrific pieces of old school D&D art. I'm usually no great fan of Jeff Dee, whose art I find too "comic book-y" for my tastes, but there's no question that his paladin illustrations remains one of my favorites.