Some locales host greater than normal concentrations of certain creatures. A few of the most notable such areas are described below.
Anauroch: Bedine humans, Netherese shades. The Bedine usually are encountered in scouting groups or patrols, both mounted on horses or camels. Bedine scouts include 1d3+1 1st-level warriors and 1d2 rangers of level 1d3+2. A Bedine patrol has 1d4+4 1st-level warriors, 1 3rd-level cleric, and 1 leader of level 1d3+3. To determine the leader's class, roll d%: 01-75, fighter; 76-85, ranger; 86-90 cleric; 91-95, sorcerer; 96-100, wizard. The Bedine can be of any good alignment
Battle of Bones: Undead of all varieties.
Bay of Chult: Dragon turtles.
Border Forest: Dryads, pixies, satyrs, sprites.
Chondalwood: Dryads, ghostwise halflings, pixies, satyrs, sprites, wild elves.
Chult: Chuuls, dinosaurs, dwarves, goblins, human tribesfolk, wild pterafolk, yuan-ti. Less common are aarakocras, hydras, nagas, troglodytes, trolls, and wyverns. Use the information on the Bedine from the Anauroch entry, above for the humans and dwarves.
Cloven Mountains: Bugbears, goblins, hobgoblins, orcs.
Cold Wood: Uthgardt barbarians; use the information on the Bedine (in the Anauroch entry), above.
Cormanthor: Drow, elves.
The Deepwash: Dragon turtles, lizardfolk.
Deepwing Mountains: Griffons, hippogriffs, manticores, red dragons, wyverns.
Dragon's Run Mountains: Hill giants, stone giants, undead giants, (patrols from Cairuheim in the Underdark). Use the statistics for huge zombies from the Monster Manual.
Dragonspine Mountains: Bugbears, goblins, hobgoblins, orcs, red dragons, and white dragons among the peaks. Stone giants, frost giants, and hill giants in lower peaks and most of the valleys.
Earthspur/Earthfast Mountains: Bugbears, drow, goblins, hobgoblins, orcs.
Flooded Forest: Assassin vines, black dragons, dark trees, lizard-folk, shambling mounds, shriekers, tendriculoses, violet fungi.
Forgotten Forest: Treants.
Forest of Wyrms: Green dragons.
Galena Mountains: Dwarves, giants, goblins. (Underdark is nearby with drow, derro, and duergar.)
Giantspires: Bugbears, hill giants, hobgoblins, ogres, stone giants.
Graycloak Hills: Elves.
Graypeak Mountains: Stone giants.
Hazuk Mountains: Stone giants.
High Forest: Centaurs, treants, wood elves.
Icelace Lake: Dire bears (on shore}
Lizard Marsh: Dinosaurs, black dragons, lizardfolk.
Long Forest: Tall mouthers, trolls.
Lonely Moor: Gnolls, leucrottas, ores, perytons, bulettes.
Marsh of Chelimber: Bullywugs, lizardfolk, sivs.
Mere of Dead Men: Lizardfolk, bullywugs, sivs.
Mhair Jungles: Wild dwarves.
Misty Forest: Hybsils, wood elves.
Moander's Road area: Fungi, oozes.
Moonwood: Lycanthropes (all types except werecrocodiles).
Naga flow/Naga water: Water nagas.
Peaks of Flame: Salamanders, other fire creatures.
Rauvin Mountains: Goblins, orcs.
Reaching Woods: Centaur, hybsils, satyr, druids.
Serpent Hills: Copper, red, and silver dragons, snakes, yuan-ti.
Southern Lluirwood: Beholders, yuan-ti.
Spiderhaunt Woods: Chitines, ettercaps, monstrous spiders of all types.
Tashalar (Black Jungles): Yuan-ti.
Trollhark Forest: Trolls.
Trollclaws: Trolls, tall mouthers.
Troll Hills: Trolls.
Troll Mountains: Bughears, goblins, hobgoblins, orcs, trolls.
Valley of Lost Honor: Batiri (human tribe), use the information on the Bedine (in the Anauroch entry, above). Also natural predators (lions, tigers, bears, and so on).
Wood of Sharp Teeth: Dire beasts, dragons, hydras.