Here is the full list of all 119 Torchlight II achievements. It takes around 200 hours to unlock all of the achievements on Windows.
Sell 50,000 items
Use 100 maps
Fish 1,000 times
Use 5,000 potions
Deal 100,000 critical strikes
Use an enchanter 500 times
Reach level 100
Find a legendary item
Have 10,000,000 gold
Purchase 100 items from the gambler
Die with a hardcore character
Obtain a tier 3 skill bonus
Break 10,000 breakables
Find 100 secret rooms
Have 1,000,000 gold
Use 10 maps
Begin new game plus
Use a map
Defeat the Nether King with each of the 4 classes
Defeat the Nether King in Elite difficulty
Defeat the Nether King in Veteran difficulty
Defeat the Nether King as an Engineer
Defeat the Nether King in hardcore mode (casual)
Defeat the Nether King in hardcore mode (elite)
Defeat the Nether King in hardcore mode (normal)
Defeat the Nether King in hardcore mode (veteran)
Sell 5,000 items
Start a hardcore character
Defeat the Nether King as an Outlander
Defeat 500 champions
Have 50 friends
Have 10 friends
Socket 500 gems into items
Defeat the Nether King as an Embermage
Use an enchanter 50 times
Destroy 100 socketed gems
Purchase 50 items from the gambler
Purchase 20 items from the gambler
Squish 1000 critters
Use 500 potions
Destroy 10 socketed gems
Recover 100 gems from items
Take 100,000 steps
Socket 50 gems into items
Explode 10,000 enemies
Trade an item with another player
Join a multiplayer game
Add a friend
Start a multiplayer game
Defeat the Nether King as a Berserker
Defeat the Nether King in Casual difficulty
Defeat the Nether King in Normal difficulty
Defeat the Nether King
Defeat the Dark Alchemist
Defeat Aleera
Defeat Verona
Defeat Marishka
Assemble TrillBot
Defeat Killbot
Defeat Vyrax
Do 10,000 damage with a single attack
Find 10 secret rooms
Defeat Thiss
Obtain a tier 2 skill bonus
Squish 500 critters
Break 1,000 breakables
Deal 10,000 critical strikes
Defeat Cacklespit
Defeat Bloatfang
Defeat the Grizzled Alpha
Defeat the Wraith Lord
Fish 100 times
Defeat Boletus Rex
Defeat the Siege Guardian
Defeat Ezrek Khan
Take 50,000 steps
Defeat Aruk
Use an enchanter 10 times
Defeat the King In Masks
Use 50 potions
Open 500 chests
Have 100,000 gold
Defeat 100 champions
Teach a pet 4 spells
Defeat the Artificer
Defeat the Manticore's Mate
Defeat the Manticore
Fish using dynamite
Teach a pet a spell
Defeat Grand Regent Eldrayn
Sell 500 items
Recover 10 gems from items
Defeat King Pogg
Obtain a tier 1 skill bonus
Squish 100 critters
Defeat Kidrik the Mauler
Destroy a socketed gem
Defeat Chillhoof
Deal 1,000 critical strikes
Defeat the Winter Widow
Explode 1,000 enemies
Recover a gem from an item
Defeat General Grell
Learn 4 spells
Find a secret room
Take 10,000 steps
Wear a completed armor set
Defeat 25 champions
Defeat Mordrox
Open 100 chests
Defeat One-Eyed Willy
Break 100 breakables
Fish 10 times
Learn a spell
Socket a gem into an item
Defeat the Fallen Guardian
Send your pet to town
Explode 100 enemies
Open 20 chests