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