d20 Monster Filter & 5e SRD Creature Search
Rebuilt for the 5e & 2024 rules era: sort iconic SRD monsters instantly by Challenge Rating, creature type, biome environment, size, Legendary Actions, and Druid Wild Shape eligibility.
How to Filter Monsters & Design Balanced D&D 5e Encounters
Originally launched on Pen, Paper & Pixel in 2004 alongside our classic d20 Encounter Calculator and Spell Filter, the d20 Monster Filter solves the biggest prep bottleneck every Dungeon Master faces mid-campaign: finding monsters that fit the exact terrain, story tone, creature type, and party power level without flipping through three separate index tables.
Understanding the Four Tiers of Monster Challenge Rating
Challenge Rating (CR) provides a fast baseline comparison against a standard four-player party, while also signaling dramatic spikes in tactical complexity as campaigns advance across the four Tiers of Play:
- Tier 1 — Local Heroes (CR 1/8 to CR 4, Character Levels 1–4): Goblins, Kobolds, Wolves, Skeletons, Owlbears, and Gelatinous Cubes shine here. At Levels 1 and 2 especially, avoid single heavy-hitting monsters like Ogres (
2d8+4average 13 damage) unless you want sudden unconsciousness—prefer small squads of CR 1/4 to CR 1/2 foes tracked easily in our Combat Initiative Tracker. - Tier 2 — Heroes of the Realm (CR 5 to CR 10, Character Levels 5–10): Once Martials unlock Extra Attack and Casters gain 3rd-level spells like Fireball and Hypnotic Pattern, Trolls, Elementals, Bulettes, Hydras, and Young Dragons test resource stamina, energy resistances, and Concentration checks.
- Tier 3 — Masters of the Realm (CR 11 to CR 16, Character Levels 11–16): Adult Dragons, Vampires, Behirs, and Iron Golems bring Legendary Resistance (3/Day), Magic Resistance, and Legendary Actions. Solo monsters without Legendary Actions lose quickly to action economy against four 13th-level heroes—always pair mid-tier bosses with skirmisher minions or hazardous terrain.
- Tier 4 — Masters of the World (CR 17 to CR 30, Character Levels 17–20): Liches, Pit Fiends, Balors, Ancient Dragons, Krakens, and the Tarrasque demand multi-layered encounter objectives, Lair Actions, and defensive dispelling rather than static slugfests.
Filtering by Environment for Believable Hex Crawls
Random encounter tables work best when the wildlife and dungeon inhabitants match the physical geography. A Swamp trek (Black Dragon, Hydra, Sea Hag, Shambling Mound, Will-o'-Wisp) should punish footing and feature Acid/Poison immunity, whereas an Underdark expedition (Aboleth, Cloaker, Black Pudding, Gelatinous Cube, Minotaur) tests darkvision, Blindsight, and tight corridor traps. Coordinate daily wilderness movement miles in our Travel Pace Calculator, stock boss hoards afterward via the Treasure & Loot Generator and Magic Items Compendium, or invent social encounters with the NPC Generator.
d20 Monster Filter FAQ
How does Challenge Rating (CR) work when filtering monsters in D&D 5e?
A monster's Challenge Rating indicates that a single creature of that CR is a fair medium encounter for a well-rested party of four adventurers of matching level. Under the 2024 Monster Manual and Dungeon Master's Guide, XP budgets per character replace old multi-monster multipliers for faster encounter balancing.
Which monster environments help build random wilderness encounters?
Official 5e monster lists organize creatures across twelve environments: Arctic, Coastal, Desert, Forest, Grassland, Hill, Mountain, Swamp, Underdark, Underwater, Urban, and Planar. Filtering by environment ensures overland hex crawls feature ecology-appropriate predators rather than out-of-place dungeon hazards.
How can Druids use the Monster Filter for Wild Shape and Polymorph?
Toggling the Wild Shape filter restricts results strictly to the Beast creature type up to CR 6, matching Circle of the Moon scaling. Both Wild Shape and the 4th-level Polymorph spell require Beast forms, whereas Shapechange can adopt any creature type within your level cap.