Below is compiled info so far. Please post corrections or additional info below. Original post kept for posterity.
Dungeons:
Hexx Ruins: Defeat Southern Swamp
Ick Swamp: Find Naga sub dungeon in Hexx Ruins after completing at least once.
Naga City: Complete Ick Swamp
Labyrinth: Defeat Western Jungle
Dragon Isle: Defeat Labyrinth
Halls of Steel(Hard): Defeat Eastern Tundra
Halls of Steel(Vicious): Defeat Halls of Steel(Hard) with 4 classes
Namtar's Lair: Defeat Halls of Steel(Hard)
Shifting Passage: Defeat Northern Desert
Demonic Library: Defeat Shifting Passage
Gaan'talet(Hard): Opened by quest progression in game and getting one of every trophy.
Gaan'talet(Vicious): Opened by completed Gaan'talet(Hard)
Races:
Gnomes: Complete quest at beginning of game
Halfling: Complete quest at beginning of game
Orc: Search Western dungeons for sub dungeon with Orc who will have you drink a potion.(Note Western Jungle seems to ALWAYS give taurog sub dungeon until completed, so druid's grove may be ideal if you do not want to unlock taurog).
Goblin: Search Southern dungeons for a sub dungeon with a goblin who wants money.(Note Southern Swamp seems to ALWAYS give Tikki Tooki sub dungeon until completed, so hexx ruins may be ideal if you do not want to unlock Tikki Tooki).
Classes:
Fighter: Guild Level 1
Berserker: Guild Level 2
Warlord: Guild Level 3
Thief: Thief's Guild Level 1
Rogue: Thief's Guild Level 2
Assassin: Thief's Guild Level 3
Priest: Church Level 1
Monk: Church Level 2
Paladin: Church Level 3
Wizard: Mage Tower Level 1
Sorcerer: Mage Tower Level 2
Bloodmage: Mage Tower Level 3
Tinker: Found in sub-dungeon enclosed by walls(Requires Alchemist unlocked).
Transmuter: Found in sub-dungeon randomly. Unknown if any pre-req.
Crusader: Found in random sub-dungeons and requires you to get to 100 piety and talk to him(pre-reqs?)
Half-Dragon: Requires completing Dragon Isle with 3 classes
Gorgon: Requires completing Naga City with 3 classes
Vampire: Requires completing Halls of Steel(Vicious) with 3 classes
Monsters:
Wraiths: Unlock Berserker Class
Goo Blob: Unlock Warlord Class
Gorgon: Unlock Rogue Class
Bandit: Unlock Assassin Class
Serpent: Unlock Monk class
Dragon Spawn: Unlock Paladin Class
Goat: Unlock Sorcerer Class
Golem: Unlock Bloodmage Class
Items:
Whhurrgll: From the Berserker quest (Punycrush McSissymage)
Trisword: From the Warlord quest (Bleaty)
Midas Gloves: From the Rogue quest (Lord Lut and Mr. Treshar)
Agnostic's Collar: From the Monk quest (Second Son)
Blue Bead: From the Sorceror quest (World of Goo)
Viper Ward: From the halfling village quest (Fangface)
Soul Orb: From the gnome village quest (Mr. Biggles)
Venom Blade: From Creeplight Contract (Assassin quest versus Anoobis)
Vampiric Blade: From the three-part Bloodmage quest in the west
Matyr Wraps: From the three-part Monk quest in the south
Witchalok Pendant: From the Halflings Ho! quest in Grim Grotto
Fire Heart: From the Ice and Fury quest (beat the berserker camp with 4 classes)
Mage Plate: From the Noises in the Dark quest (beat the Labyrinth with 4 classes)
Battlemage Ring: From the Minecraft quest (beat Magma Mines with 4 classes)
Hero's Helm: Confidence quest in Den of Danger
Zombie Dog: From completing quest to win Den of Danger with first tier classes.
Crystal Ball: From completing quest to win Den of Danger with second tier classes.
Dragonshield: Lockerable artifact from Dragon Isles(Last Boss Drops instead of trophy).
Avatar's Symbol: Lockerable artifact from Demonic Library(Last Boss Drops instead of trophy).
Namtar's Ward: Lockerable artifact from Namtar's Lair(Last Boss Drops instead of trophy).
Sensation Stone: Lockerable artifact from Havendale Bridge(Dropped by bridge troll if defeated). Can also be acquired within Gaan'talet on troll floor.
Gods:
For all gods, once you have touched the alter and leave the sub-dungeon they are unlocked. You can retire or die or complete.
Glowing Guardian: Found in the East(Sub dungeon with path and 3 zombies of increasing level)
Dracul: Found in the East(Sub dungeon with your clone, you are locked in) (prerequisite: glowing guardian)
Mystera: Found in the North(Sub dungeon with 999 hp dragon, creative use of magic will get you past him)
Jehora Jeheyu: Found in the North(Sub dungeon has imps and an alter) (prerequisite: mystera)
Taurog: Found in the West(Sub dungeon.. large room with taurog alter at the center)
Binlor: Found in the West(Sub dungeon small room surround in walls, smash walls to find alter)(prerequisite: taurog)
Tikki Tooki: Found in the South(Sub dungeon with Imp that blinks and has death protection, chase it through stairways)
Earthmother: Found in the South(Sub dungeon filled with plants)(prerequisite: tikki tooki)
Pactmaker: Found anywhere(Sub dungeon giant room with alter in the middle, touch alter 3 seperate times to unlock) (prerequisite: Unlock any god)
Buildings:
Witch: I found this in the eastern tundra after many many many tries. Get a quest inside to collect 5 items by killing plants.(This may be harder to find if you do not unlock Dracul because that has a high chance of spawning).
Alchemist: Buy Philospher's stone and exit the level without dying.
Bazaar: Buy Portal scroll and exit the level without dying.
Bank: Will receieve quest.
**** BELOW IS ORIGINAL POST ****
Ok so there seems to be a focus lately on specific unlocking. However, I can't find any detailed information on where or how to unlock various things whether it be gods, items, classes, races or dungeons. Part of the problem is that the search function on the forums seems to dislike any word I use and claims it is too common.
I figure with people having been starting new profiles it might be good to document this information somewhere as people rediscover it.
So specifically the information *I* want to know is:
1) What items are unlocked specifically by which easy quests.
2) How do you unlock orc/goblin? Is it random and you can expect to reload dungeons 1-100 times or are there specific places that they appear? Are there prerequisites?
3) What dungeons are necessary to open the various vicious dungeons.
4) Where do you find the tinker? Is it random? Are there prerequisites?
Beyond that I would be happy to update this first post on any unlock info provided so EVERYONE can have a resource until such time that it is worth updating the wiki.