I was wondering what kind of enemies you guys like to pit your PCs against! Goblins, Duregar, Slaadi, regular old mercenaries? Lemme know your favorites, and how you like to incorporate them!

Xvarts.  I think it was an "x" thing to start with the original Fiend Folio Tome and as they seemed to waver through the editions I always kept them going.  Besides I had painted a few gobbos from Citadel Miniatures to be xvarts and they're so damn cute!  They're almost my default "low level" humanoid in a lot of games just to change things up from goblins & orcs, especially with players that are new to me.  My first convention game I ran was all based on a xvart lair and their jury-rigged ballista shooting down gryphon knights.  

I am not a fan of the 5E treatment.  I am going to call that a "Realms" thing.  Raxivort was a Greyhawk diety!  Realms, always stealing other gods, Tyr, Mielliki, bah!  *stomps off to his home-brew setting with it's 90% recycled pantheons*  

Political groups. So mostly humanoid. Something very 'fleshed out' about having enemies you can fight, talk to, have agendas, etc. It allows encounters to be creative and an ebb and flow to interaction.

If I had to pick a particular race/culture, I'd say shamanic tribes. 

Nice reminder, BigBuck, in my Greyhawk games I always have to have the Scarlet Brotherhood in the shadows in some way, even if it's no more than a "Boogie Man" story.  Sean K. Reynolds's Scarlet Brotherhood book was full of so many nuggets I have to keep the rumour mill going.  If I could only find players that can pull off the LE alignment, I'd run my Scarlet Cell game again.  Anyway, political groups are great reoccurring villains.

There are only a few constants in my campaigns when it comes to monsters involved; there will always be some kinds of undead involved, and if the party goes into the kind of places that make sense for a beholder to be they are almost assured to run into at least one beholder.

Other than that, I try to incorporate as many monsters I haven't used before/recently as I can make sensible given the campaign.

I love having enemies that the PCs can talk to and find out secrets about, but I really like to do this with unexpected enemies. I think it really can turn a game on it's head when the goblin leader suddenly asks for the party's help, or when an uneasy alliance is struck between the PCs and an enclave of kobolds. Giving a political structure to monsters as well as people can create some eerily noncombat encounters with monsters that I always think is fun.

I use Cultists. It's funny because my players (somehow) get like 3 nat 20s in a row and just obliterate a Cultist who has like 9 HP. I've debated saying that the cultist just ends up looking like sludge after the hit

Quote from VanZoeren >>

I was wondering what kind of enemies you guys like to pit your PCs against! Goblins, Duregar, Slaadi, regular old mercenaries? Lemme know your favorites, and how you like to incorporate them!

 I don't like recurring enemies. Even with different campaigns I try not to use the same type of enemies. So Campaign #1 may have kobolds and goblins campaign 2 is going to have orcs, and duergar. And then its going to change throughout the game. 

Blights, oddly enough. I like their creepy-but-weirdly-cute designs, they synchronize well together, and they’re created by evil trees and that’s cool.

I think I fall into a trap of most disposable enemies being human males. I mean, I really prefer unique monsters - but that said, most other encounters tend to be human males, usually a caster with some archers and swordsmen.

Maybe I should work on that. 

I like to keep to themes, with the campaign. Currently they have Yuan-Ti and Giants as their main problems. I also try not to creep the power of them as they level up - I want them to get to a higher level and realise that giants can be felled in 1 round, and yuan-ti can be scythed like wheat! Then, they may respond by bringing in bigger guns. We shall see!

lets see. my current campaign is all about the BBEG causing rips in reality so things from elsewhere can slip though. so I created a dozen monsters. basically all sub-CR 1 creatures with a unique twist. my favorite has to be number 8. basically a giant spider, with no web action, extra lightning damage instead of poision, and a bite attack with a range of 15ft, suggesting that it has a 15ft long neck. on a spider's body.

Quote from ThorukDuckSlayer >>

I like to keep to themes, with the campaign. Currently they have Yuan-Ti and Giants as their main problems. I also try not to creep the power of them as they level up - I want them to get to a higher level and realise that giants can be felled in 1 round, and yuan-ti can be scythed like wheat! Then, they may respond by bringing in bigger guns. We shall see!

 In the 7 (seven!) years since posting this, I've done a lot of DMing, and I have to say this is my favorite take. Most of my campaigns or story arcs revolve heavily around themes and even different genres of play. Right now my high level party is in a Barovia-esque timeloop arc, with time resetting every two days.

They're trying to get to the final boss, but need to gather certain information and supplies beforehand. Each new "cycle" I'm introducing more Gothic horror creatures to fight, and they're getting closer to The Truth. Keeping a tight theme is a really fun way to play. It definitely keeps the game feeling fresh when not everything is the same monster/fight over and over. 

Quote from VanZoeren >>

Quote from ThorukDuckSlayer >>

I like to keep to themes, with the campaign. Currently they have Yuan-Ti and Giants as their main problems. I also try not to creep the power of them as they level up - I want them to get to a higher level and realise that giants can be felled in 1 round, and yuan-ti can be scythed like wheat! Then, they may respond by bringing in bigger guns. We shall see!

 In the 7 (seven!) years since posting this, I've done a lot of DMing, and I have to say this is my favorite take. Most of my campaigns or story arcs revolve heavily around themes and even different genres of play. Right now my high level party is in a Barovia-esque timeloop arc, with time resetting every two days.

They're trying to get to the final boss, but need to gather certain information and supplies beforehand. Each new "cycle" I'm introducing more Gothic horror creatures to fight, and they're getting closer to The Truth. Keeping a tight theme is a really fun way to play. It definitely keeps the game feeling fresh when not everything is the same monster/fight over and over. 

 Sounds like a cool campaign!

Recently I decided to remind the party how powerful they are, and had a group of bandits accost them on the road. They responded initially with violence, and then talked it out after they basically vapourised the CR1/2 bandits who didn't know they were accosting a level 13 party. The group was used to the encounters tending toward a challenge, so it's worth saying "you do enough damage to kill 20 people with that spell" every so often so they realise that they're making progress!

Same with the Giants - when they first met them they were level 9, I believe, so they were a challenge. Now they're level 13, and I haven't boosted the giants to match them (though there will likely be more of them) so they can get the feeling of progress!

Troll. Need I say more?