Monsters get a saving throw against some effects, most notably bolt spells. This save almost always looks like (SR - (Attack / 2))%, where SR is a property of the monster type only. Attack is something on the scale of your experience level.

0	Ancient Stone Beast, Snake from Beyond, ancient karmic dragon, ancient karmic wyrm, ancient minotaur, animated tree, ankheg, arena master, assassin, assassin prince, bandit, barbarian, barbarian leader, beggar, berserker, berserker emperor, berserker king, berserker lord, berserker prince, big casino guard, big dog, black baby dragon, black hurthling, black slayer, black wizard, blink dog, blue baby dragon, brown bear, brown worm, bugbear, bulette, carpenter, carrion crawler, casino guard, cave bear, cave fisher, cave lion, cave lizard, cave tiger, caveman, chaos brother, chaos lizard, chaos plague bearer, chaos rat, chaos servant, chaos sister, chaos spawn, chaos spider, chaos viper, child, claw bug, cloaked ratling, cobra, crime lord, cute dog, cutpurse, cyclops, dark orc, death ooze, demented ratling, diamond golem, dire wolf, displacer beast, doppleganger, doppleganger lord, dragon turtle, dwarf, ettin, farmer, fire beetle, fire giant, fire giant king, fomorian giant, fool, frost giant, frost giant berserker, frost giant jarl, gargoyle, gelatinous cube, ghost, ghost bat, ghost king, ghost lord, ghul, giant ant queen, giant ant warrior, giant ant worker, giant bat, giant bee worker, giant boar, giant centipede, giant dragon turtle, giant eel, giant frog, giant lizard, giant raccoon, giant rat, giant shark, giant slug, giant spider, giant turtle, gibbering mouther, gnoll, gnoll chieftain, goblin, goblin berserker, goblin chieftain, goblin rockthrower, goblin slavemaster, goodwife, gray ooze, gray slayer, great karmic wyrm, greater claw bug, green blob, green slime, green worm, griffon, grizzled gladiator, grizzly bear, half-orc bouncer, harpy, healer, hill giant, hill giant chieftain, hill orc, hill orc sergeant, hippogriff, hobgoblin, hobgoblin chief, hobgoblin leader, huge bat, hydra, hyena, jackal, karmic baby dragon, karmic dragon, karmic lizard, killer bug, king cobra, large bat, large dog, large gnoll, large jackal, large orc, large snake, large spider, leucrotta, lizard man, mad carpenter, malicious doctor, margoyle, master assassin, master swordsman, master thief, minotaur emperor, minotaur king, minotaur lord, minotaur mage, minotaur mazelord, minotaur mazemaster, mugger, necromancer, ochre jelly, ogre, ogre emperor, ogre guardian, ogre king, ogre lord, orc, orc butcher, orc chieftain, orc scorcher, outlaw, outlaw leader, owlbear, pit viper, purple worm, rabid dog, raider, raider lord, rat, ratling archer, ratling dealer, ratling duelist, ratling fencer, ratling guardian, ratling master thief, ratling rebel, ratling thief, ratling trader, ratling warlord, ratling warrior, rattlesnake, red baby dragon, red worm, shadow centipede, shadow troll, shambling mound, shark, sheriff, silver wolf, small dwarf, stone giant, stone giant lord, stone ooze, swamp hydra, swordsman, tarantula, thug, tiny girl, troll, troll berserker, troll chief, troll king, vapor rat, village elder, viper, wererat, werewolf, werewolf lord, white baby dragon, white worm, wild cat, wolf, yellow ooze
1	battle bunny, mutated battle bunny
2	skeleton
5	fire lizard, giant bee warrior, kobold, kobold chieftain, kobold shaman, lightning lizard, old barbarian
10	corpse fiend, dwarven child, dwarven elite guardian, dwarven guardian, dwarven inn keeper, female dwarf, gorgon, large kobold, magebane eye, minotaur, muscular dwarf, priest, stone snake, water snake, zombie
15	fire drake, jackalwere, rust monster, werewolf king, white dragon
20	annis hag, black dragon, bunny master, burly adventurer, chaos wizard, dark sage, gremlin, magedoom eye, mimic, moloch, skeletal warrior
25	blue dragon, floating eye, giant rust monster, hell hound, imp, large rust monster, least daemon, shadow, slow shadow, spectre, staring eye, wight
30	ElDeR cHaOs GoD, acid vortex, chaos warrior, corruptor, fire vortex, flesh golem, giant bee queen, greater chaos servant, ice vortex, lightning vortex, mad doctor, pixie, pixie archer, red dragon
33	druid
35	black druid, dark elven archer, dark elven princess, dark elven warrior, greater mimic, green hag, homunculus, invisible stalker, lich, living wall, master mimic, mimic hivemind, mummy, ogre magus, quasit, royal guardian, steel zombie, vampire, wraith
40	annihilator, skeletal king
45	air demon, air grue, ancient black dragon, ancient blue dragon, ancient red dragon, ancient white dragon, baby water dragon, chaos mutant, cooshoo, dwarven weaponmaster, jackal demon, old crone, quickling, quickling lord, shadow wyrm, water demon, water grue
50	Master Summoner, air elemental, chaos warlord, crystal statue, dark elven lord, djinni, dwarven smith, earth elemental, fairy dragon, fire elemental, great blue wyrm, greater moloch, lesser daemon, quickling king, quickling queen, shadow lord, stone statue, water elemental
55	dark elven wizard, great white wyrm, revenant
60	Ancient Chaos Wyrm, animated armor, great red wyrm, greater air elemental, titan, wall beast
65	balor, fire demon, great black wyrm, greater mummy, master lich, oracle, writhing mass of primal chaos
70	doppleganger king, greater water elemental
75	Dorn Beast, Mad Minstrel, banshee, cat lord, chaos knight, dark elven priestess, dwarven artificer, dwarven chaos knight, fire grue, ghost librarian, greater daemon, greater earth elemental, greater fire elemental, holy slayer, lich king, master necromancer, undead chaos dwarven berserker
80	ancient blue wyrm, clay golem, emperor moloch, multi-headed chaos dragon, stone grue
85	greater balor, mummy lord
88	will o'wisp
90	bone golem, great water dragon, greater titan, ki-rin, stone golem
95	ancient dwarf, chaos eye, emperor lich, eye of destruction, quickling bard, solar, steel horror
96	shopkeeper
100	black unicorn, dwarven mystic, eternal guardian, eternium golem, greater black unicorn, greater white unicorn, iron golem, steel golem, white unicorn
120	Chaos Archmage
500	ancient sage, dying sage