D&D 5E No Monster Manual Monsters

[Reynard]

I am starting a megadungeon exploration campaign soon, and most of the potential players are old hands. As such, I want to populate the place with interesting, unexpected monsters from the lowliest mook the biggest bad. I am running the game on Fantasy Grounds and own Volo's, Mordenkainen's and the Tome of Beasts. I may be convinced to buy the Creature Codex, or another (preferably cheaper) bestiary. I don't mind building na few new monsters or converting from, say, Pathfinder, but I would rather put most of my efforts into dungeon design.

What creatures would you suggest to fill the niches left empty by eliminating the likes of kobolds, goblins and orcs? What is a good replacement for weird trick monsters like the rust monster or the mimic? What big bads replace the dragon, the lich or the mind flayer?

Thanks!

 

[MNblockhead]

First, Tome of Beasts is great, good choice. Creature Codex is really good, but some of the monsters just feel less inspired. Frog God Games also publishes some good bestiaries. Personally, I prefer Kobold Presses bestiaries over FGGs, but I've been running a Lost Lands campaign centered around Rappan Athuk and playing FGG monsters in the FGG setting has given me a new appreciation for them.

Instead of kobolds, goblins, and orcs, you can use:
* grung (Volos),
*various intelligent plant folk (vegepygmies from Tomb of Annihilation)
*gremlins (Tome of Horrors by FGG)
*gribbons (flying monkey creatures in Tome of Horrors)

Also you don't need to completely replace orcs, goblins, but look into all the variants for these races in Tome of Beasts, Creature Codex, Tome of Horrors, 5th Edition Foes, etc.

When it comes to big bads, just look at the challenge rating tables in KP or FGG bestiaries. Note that I find Kobold Press monsters to be more difficult than those of similar CR in WotC books.

 

[GMMichael]

What creatures would you suggest to fill the niches left empty by eliminating the likes of kobolds, goblins and orcs?

Humans. They can be pretty nasty.

What is a good replacement for weird trick monsters like the rust monster or the mimic? What big bads replace the dragon, the lich or the mind flayer?

You can cheat here by reskinning the typical big bads. A huge statue of a griffon animates, using dragon stats. A red-skinned goblin has tentacle-fingers and does the same things a mind flayer would. The lich uses stats for some big demon instead.

That should keep the old hands guessing for a round or more. As for "interesting," just grab a bestiary from a non-fantasy RPG or maybe a video game, and use those for your skins.

 

[Ralif Redhammer]

For basic goblinoid replacements from those sources, the Ratfolk spring to mind. There are more of them in the Creature Codex, too.

As for replacing the mind flayers, there are bunch of eldritch cosmic horror beasties that spring to mind, like the Mi-Go. And there are tons of cool undead.

 

[aco175]

What @DMMike said. Just because the MM says that goblins have 7HP, your goblins may not. The book may just be lore your world collected and your players need to take with a grain of salt. Feel free to add powers and abilities to make them fit.

You can also go with some of the low-level monsters. I always let the PCs know some of the common things that monsters have assuming that the PC grew up in my world. Everyone knows that trolls need fire to kill and adventurers would know that acid does the same thing. Many locals may only know about the fire. Everyone knows that skeletons need bludgeoning, but watch the surprise when you have a skeleton knight with damage reduction.

 

[Reynard]

The Hellstair (my megadungeon) is a weird place, where the deeper you go the laws of physics and things that are objectively true matter less and less. But even near the top layers there are things in there that are found nowhere else.

Now, @DMMike has a good point. I think in the early levels the most dangerous things are probably other "adventurers." Why risk your life going down in that hole when you can just lay in wait for a group of exhausted, resource poor, wounded folks carrying out your gold and magic trinkets for you?

 

[Swarmkeeper]

Pay what you want:
Nerzugals-Dungeon-Master-Toolkit-2 (over 100 monsters)
Nerzugals-Extended-Bestiary (ditto - these are the ones that appear in the Game Master Toolkit, which is different than the DM Toolkit)
The-Buccaneers-Bestiary (from EN World's very own contributor @Quickleaf)

 

[Blue]

Reskin and tweak. Oh, grab some traditionally good creatures that the players may not have fought.

The large spirit-like nightmares that regenerate immediately unless you hit them with radiant, necrotic or lightning damage? Trolls.

The thick-skinned armor-plated stink rhinos? Hezrou demons. Horn, claw, claw instead of bite, claw, claw.

Gelatinous tentacle beast that keeps assuming other gelatinous forms and has high casting? Couatl.

The group of "hobgoblins" with spiked chains? Really in your world those are Chain Devils with a replacement for Unnerving Mask. That act like hobgoblins with martial precision.

And then do things just close enough to mess them up. Like the Blue Dragon that actually uses Bronze dragon stats, so it has a repulsion breath in addition to it's lightning breath.

Throwing them something the recognize but only sometimes twisting it is a great way to make them unsure.

Plus, you have the whole internet. You can do it.

 

[Celebrim]

I don't really know what has been converted to 5e, but I'd be happy to help in that regard.

What creatures would you suggest to fill the niches left empty by eliminating the likes of kobolds, goblins and orcs?

Xvart, Dark Creeper/Dark Stalker, Derro, Quickling, Mephit

What is a good replacement for weird trick monsters like the rust monster or the mimic?

Stun Jelly, Trapper, Lurker Above, Zorbo, Enveloper

What big bads replace the dragon, the lich or the mind flayer?

Thessalhydra, Spirit Naga, Death Slaad, Umber Hulk, Kopru

 

[jayoungr]

If you want something that will keep your players guessing, Fifth Edition Foes from Frog God Games is a good choice. It was published very early in 5E's lifespan and incorporates some pretty old-school design elements/assumptions--for example, there's a lot more magic resistance and immunity than in many monster collections. (The cover says "Fifth Edition Rules, First Edition Feel.") Most of the monsters have some form of special mechanic or ability.