Single Monsters
Min Monster Level = 0.75*CharacterLevel - 10
Max Monster Level = 1.1*CharacterLevel + 1

Pack Monsters
Min Monster Level = 0.6*(CharacterLevel - 20)
Max Monster Level = CharacterLevel - 20

MONSTERS IN RANDOM ADVENTURE
Level Monster
0 Frogzard
0 Icezard
0 Potion Treasure Chest
0 Firebird
0 Rare Treasure Chest
0 Huge Rat
0 Strange Little Dude
1 Drakel Caster
1 Undead Knight
1 Firezard
1 Energyzard
1 Giant Spider
1 SkySeeker
1 Sunray
1 Blecch
2 Deathwood
2 Drakel Warrior
2 Seed Spitter
2 Vagaran
2 Torch Foot
2 Animal Box
2 Evil Eye
3 Darkzard
3 TadZard
4 Wasp Swarm
4 Arroc
4 Drakel Water Mage
4 Zzott
4 Snayl
4 Fire Drakel Warrior
4 Sickly Zombie
5 Crabee
5 Undead Archer
5 Undead Soldier
5 Undead Troll
5 The Bloatt
5 Piranhas
5 Dark Knight
5 Dragon Blade?
5 O'Teeny
5 Mermazon
5 Sarkanian
5 Undead Ribber
6 Mud Golem
6 Ice Golem
6 RayZard
6 Mantik
6 Fire Mantik
6 Fire Seed Spitter
6 Undead Paladin
7 Windzard
7 IceSnayl
8 Snow Warrior
8 Glayser
8 Gnarl
9 Stone Golem
9 Fumidus
9 MiniWorm
9 Lesser Zombie
10 Razorwing
10 Vampire Bat
10 Drakel Enforcer
10 Fire Fiend
10 Fire Drakel Wizard
10 Ice Knight
10 Wild Worm
10 Brigling
10 Drakel Power Scout
10 Gnuvain the Changer
10 Orc Footsoldier
10 Gris Dingle
10 Dark Cave
10 Dark Cave
10 Mermazon Archer
11 Mawler
11 Fire Knight
12 Glow Worm
12 Prismix
12 Frazzlhutch
12 Worm Caster
13 Undead Wounded
13 Quizzat
13 Chrask
14 Undead Mage
14 Berserker Worm
14 Dwakel
15 Mermazon
15 Undead SpellSword
15 Wun-Dead
15 Whomp
15 Hell Hound
15 Two-Bear
15 Cyclops
15 SkyHunter
15 Soldier Wasps
15 Young Minotaur
15 Garganth
15 WhaleZard
15 CloudZard
15 NightZard
15 LightZard
15 ToadZard
15 BlizZard
15 StormZard
15 Undead Moglin Knight
15 Hybee Scout
15 Razorclaw
15 Malgru
15 Undead Paladin
16 Velociraider
16 Demon Cat
16 IceShifter
16 InfernoZard
17 Gargoyle
17 Worm Knight
17 Dastardly Gloop
18 Zeel
18 Shevite
18 Worm Rider
18 Young Fire Dragon
18 Young Darkness Dragon
19 Dwarf Warrior
19 Chomper
20 Emerald Slime
20 Magman
20 Frost Giant
20 WereBat
20 Forest Demon
20 Zard Ice Pack
20 Little BURP
20 Gnuvain the Changer
20 Zombie Knight
20 Orc Archer
20 Fire Ants
20 Battle Whale
21 The Unseen
22 D.R.O.U.S.
22 Seadog
23 Drakel Air Raider
23 Orc Swordsman
23 Undead Paladin
24 Weather Witch
24 Hydrak
25 Fire Golem
25 Clawg
25 Griffin
25 Grizzle
25 Demon Tree
25 Skeeter
25 Sand Shark
25 Death Witch
25 Four Eyed Freak
25 Undead Freak
25 Moglin Freak
25 Orc Mage
25 Orc Gladiator
25 Sneak
25 Drakel Ice Mage
25 NinjaZard
26 Phoenix
26 Bright Sunray
26 Moonray
27 Lectro
28 Mjolnid
28 Blecch
29 Grunt
29 Ferocious Chrask
30 Kresh
30 MotherZard
30 Hell Piranhas
30 Slaxe
30 Light Sentinel
30 King Cobra
30 Ice Warlord
30 Emerald Golem
30 Drakel Water Raider
30 Troll
30 The Seeker
30 Pygmy Zombie
30 Merchant
30 Hybee Scout
30 Orc Bandit
31 Undead Commander
32 Lesser WarBeast
32 Draegan Avenger
32 Mondrogor
33 Fire Warlord
33 Sorceress
33 Little Gogg
34 Thrachee
34 Plodd
35 Braken
35 Undead Giant
35 DarkShifter
35 Drakel Destroyer
35 Fire Cobra
35 Ice Burrower
35 Undead Skull Knight
35 Sneak
35 Umazen Bandit
35 Paladin Axe Master
35 Undead Paladin
36 Gorarog
36 Mummicane
36 Demon Steed
36 Terropain
36 Stat Roller
37 Ruby Golem
38 Salamander Hatchling
38 Szniflip
39 Forgah
40 Adalon
40 Minotaur
40 WereWolf
40 Snow BunnyZard
40 Junior Zard Pack
40 Zombie
40 BURP
40 Beldak
40 Mermazon Archer
41 Searlok
42 Iron Golem
42 The Horror
42 Undead Paladin
44 Zzzzzzott
44 Drakel Power Armor
44 Mermazon Berserker
44 DemonSpectre
45 Yeti
45 Grandmother Zard
45 Giant Nautoid
45 Slattwob
45 Hybee Scout
45 Gizzard
46 Legendary Warrior
47 Fire Eater
47 Angry Protester
48 Demon Panther
50 Greater WarBeast
50 Animal Box
50 Altidont
50 Zarlath
50 Necrofiend
50 Fire Demon
50 Ice Demon
50 Undead War Party
50 Giant Chicken Trobble
50 Croaker
50 Gnuvain the Changer
50 Xyfrag
50 Sneak
50 Samurai Warrior
50 Undead Ribber
50 Paladin Captain
50 Undead Paladin
51 Sarkanian
51 Fire Gloop
52 Gargel
52 Velociraider Rex
52 The Seeker
53 Berserker
53 Djinni
54 Tundra Reaver
54 Ghoul
55 Light Demon
55 Water Dragon
55 Big Zombie
55 Drakel War Party
55 Dragoo
55 O'Meany
55 Battle Whale
56 Cyclops Defender
56 Undead Berserker
57 Creech
57 Griffin Queen
58 Hungry Braken
58 Undead Basher
60 Chimera
60 Minotaur Prime
60 Big BURP
60 Savvy Merchant
60 Hybee Scout
60 Sarkanian Bladesman
60 Warrior Troll
61 Sphinx
62 Thunderbird
63 Elite Frogzard
63 Four Eyed Menace
63 Banshee
63 Razorclaw
64 Sea Titan
64 Zadd the Golem Builder
64 Sarkanian Charioteer
65 Darkness Dragon
65 Behemoth
65 Avalurch
65 Umazen
65 Acidragon
65 Undead Paladin
66 Death Knight
66 Cyclops Chieftain
67 Gogg
67 Cthulion
69 Pirrelvag the Blizzard Dragon
70 Serlissa the Water Dragon
70 Vampire
70 Fire Ants
71 Fire Orbs
71 Rascally Sheepbiter
72 Night Terror
72 Sun-Eater
72 The Roc
72 Acid Spitter
73 The Seeker
74 Centocor
74 Umazen.com
75 Dracolich Rider, (Undead Dragon)
75 Hybee Scout
75 Sneak
75 Undead Paladin
76 Big Salamander
76 Michaelon Entan
77 Edan the Fire Dragon
77 Drowned Angry Rat
77 Elf Power Armor
78 Magman Superior
78 Deadly Natator
79 Drakel Swordmaster
80 Trigoras the Dragon
80 Shadowfire Knight
80 Rabid BURP
80 Zard X-3
81 Xarav
81 Deadly Wind Wasps
82 Sea Brigling
82 Battle Troll
82 Mondrogor
83 Aquus
84 Supreme Iceshifter
85 Plasma Dragon Lord
85 Hydra
85 Elite Zeel
85 Krathan the Centocor
85 Pheron
85 Undead Paladin
86 Grand Sphinx
88 Kharssal
88 Kelp Ball
90 VorpalZard
90 The Reaper
90 Moglin UberFreak
90 SuperMegaUltraGigaworm
90 Hybee Scout
90 Malgru
90 Sneak
92 High Paladin
92 Megogg
92 Lightbringer
92 Thunder Troll
92 Pzycho Fiend
94 Supreme Darkshifter
95 Entromorph
95 Ziragat (undead dragon)
97 The Seeker
98 Huge Salamander
99 Mr. Worm
99 Kitten of Doom
100 Sila
100 Adult Battle Whale
111 Banshee Messenger
112 Night Horror
113 Sine qua non
114 Mythical Warrior
115 FlibbitiestGibbest
116 Tropopause Tyrant
117 Klubber, the Undead Dude
118 Bruce the Soralag (Dragon,Drakel)
119 Dire Shade Dweezel, Dragon
120 Ultra Akriloth, Dragon
140 ArMegoggon

MONSTERS REMOVED FROM RANDOM ADVENTURE
Level Monster
0 Jaques
0 Sir Pwnsalot
0 Truth
2 Centaurion
10 Ganzard
10 O'Meany
20 O'Greeny
25 O'Meany
35 O'Greeny
40 O'Meany
50 Kibbles the Happy Elf
50 O'Greeny
60 Captain Rhubarb
60 Xyfrag
65 O'Greeny
70 O'Meany
70 Xyfrag
75 Dweezel
75 Krenos
80 Akriloth
80 O'Greeny
84 Gorgon
85 O'Meany
95 O'Greeny
96 Hirroo
96 Qubak
98 Zombie Overlord
100 Xyfrag
108 Carnax

Source

Suikoman444, http://forums2.battleon.com/f/tm.asp?m=3723849