A plethora of monsters

[Dawgmoah]

Idle curiosity: when you run a game, how many monsters are you using? What are your sources? Do you bother optimizing them or changing them so the players can't just grab the Monster Manual to read up on it or something?

I usually stick with the WOTC monster books, 3.5, but I know there are plenty of other books and sources out there. I've made few monsters and grabbed a few off of boards. I think in the books there are about 1,000 or so monsters.

How many are actually used in a game though?

[GilesTheCleric]

I typically use any monster listed on WotC's index of monsters, since it's very easy to search by CR or type for whatever situation I have in mind. Generally I avoid MM1 stuff, since I assume that the players have all of it memorized. If I do use anything from it, I generally do a slight amount of re-fluffing or stick them into places where they might not be expected.

I have tokens for just over 1,600 monsters, but there's definitely some I missed (anything with art that isn't hosted on WotC's servers). Browsing all of the tokens for something interesting helps me to figure out what sorts of encounters I might run, and helps me to break away from my preference for certain monster types.

[Urpriest]

I use whichever monsters the situation and theme calls for. Usually, this tells you which books to look into: for example, if you've got Illithid foes, you should probably look at Lords of Madness and Underdark.

Generally I use monsters as-written (after a quick check that their stats are in order), but I try to throw in at least one modified monster per session, since it's the closest the DM gets to character generation, which is the most fun part of D&D 3.5.