I've got a few that I've posted in a Reddit thread before, I might add onto it if I feel like it later.
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"Down in a Hole" - Fall 3000 feet without interruption.
"South of Heaven"- Reach the absolute bottom of the world.
"The Great Gig in the Sky"- Reach the absolute top of the world.
"Junkhead"- Completely fill your inventory.
"Hit the Lights"- Wire your first set of lights that can be turned on and off, and then do so.
"Dressed to Kill" Put on the suit jacket and pants, sunglasses, and have a form of handgun in your inventory, such as the flintlock pistol, the handgun, or the Phoenix.
"Peace Sells... But Who's Buying?"- Sell a bullet-based hardmode gun to any NPC.
"Steal Away (The Night)"- Have you and all your NPCs survive a Blood Moon.
"Invaders"- Have you and all your NPCs survive a Goblin Army.
"Fairies Wear Boots"- Equip both Spectre Boots and either Angel/Demon wings at the same time.
"Strength Beyond Strength"- Use your first Life Crystal to boost your max health.
"Holy Diver"- Come within 20 health of drowning but survive.
"Whiplash"- Create/get your first Hook.
"Altar of Sacrifice"- Destroy a Demon Altar from entering hardmode.
"Caught in a Mosh" or "Flash of the Blade"- Kill three enemies with a single swing of a melee weapon.
"Metal Thrashing Mad"- Kill 20 enemies in a row with melee weapons.
"Welcome Home (Sanitarium)"- Use your Magic Mirror to teleport home.
"Aces High"- Kill an airborne enemy with a ranged weapon while airborne yourself.
"Rattlehead"- Make a complete set of armor (ie, a complete iron set, a gold set, etc.)
"Killing is my Business... and Business is Good!"- Defeat every boss in the game.
"Don't Talk to Strangers"- Find the bound Goblin Tinkerer, the Mechanic, or the Wizard, but leave them behind.
"Spiral Architect"- Make a suitable housing structure that has at least 500 tiles (squared) of space.
"Straight through the Heart"- Kill someone on your friend list in a PVP match.
"Cemetery Gates"- Make a cordoned-off room with a dirt floor, containing at least 10 tombstones.
"A New Level"- Enter Hardmode.
"Sabbra Cadabra"- Kill Tim and equip the Magic Hat.
"Them Bones"- Free the Old Man from his curse.
"War Ensemble"- With the help of at least 3 other players total in a server, defeat a boss.
"Flesh Storm"- Kill ten enemies in ten seconds or less.
"Children of the Grave"- Die as a Hardcore character.
"Snowblind"- Build a suitable housing inside a snow biome.
"Good Friends and a Bottle of Pills"- Heal at least 80% of your depleted health by talking to the Nurse.
"Sacred Heart"- Use enough Heart Crystals to reach 400 health.
"Shoot Shoot"- Have every bullet-based gun in the game in your inventory at once.
"Born of Fire" or "Voodoo"- Sacrifice the Guide in the Underworld.
"Chemical Warfare"- Create your own alchemy station and brew your first potion.
"Heaven and Hell"- Travel from a Hallowed Biome to a Corrupted biome within 30 seconds.
"Five Minutes Alone"- Go AFK and don't do anything for five minutes, don't move and don't get attacked.
"Hangar 18"- Make a Space Gun.
"Sleeping Village"- House all of the NPCs in one interconnected building.
"Behind the Wall of Sleep"- Get behind the Wall of Flesh while fighting it.
"Divine Intervention"- Have a Falling Star steal your kill.
"Seasons in the Abyss"- Stay in the Underworld without surfacing for a complete in-game day.
"Got the Time"- Craft and place a Grandfather Clock, while having an active watch in your inventory
"Master of Puppets"- Find the Guide Voodoo Doll.
"Fear of the Dark"- Stay inside for an entire night.
"The Conjuring" or "The Call of Ktulu"- Summon the Wall of Flesh.
"Aerials"- Stay in the air for twenty seconds.
"Wasted Years"- Sell an artifact that you can only find from dropped from the Wall of Flesh.
"Sickman"- Get the Poisoned debuff while you are poisoning another mob.
"Dirt"- Carry at least 4000 dirt blocks in your inventory at once.
"Man in the Box"- Kill a Mimic.
"Misty Mountain Hop"- Using only materials found in nature, make a 'mountain' at least 700 feet in height.
"Bible Black" or "Black Magic"- Find and equip a Demon Scythe.
"Spill the Blood"- Bleed out from the 'Bleeding' debuff.
"Live Undead"- Get overrun by zombies during a Blood Moon.
"Crypts of Eternity"- Raid every locked chest from the Dungeon.
"Into the Void"- Stay in the Space-ish biome for a full in-game day.
"Playing with Dolls"- Set up at least 5 Mannequins in the same room with complete armor sets on them.
"After Forever" or "Heaven Can Wait"- Die in the Underworld.
"Running Free"- While having Hermes or Spectre boots equipped, lose 90% of your health and regenerate it all naturally.
"She-Wolf"- Transform into a Werewolf using the Moon Charm.
"Cowboys from Hell"- Kill 5 demons in the Underworld while under 50% health.
"No Quarter"- Have at least 5 platinum coins in your inventory.
"In my Time of Dying"- Die 5 times in 5 minutes.
"A Pound of Flesh"- Make both the Archeologist's Jacket and Pants.
"Trampled Under Foot"- Get crushed by a boulder trap underground.
"Fear the Voices"- Ignore the warnings and summon the Eater or Worlds by smashing Shadow Orbs.
"Die Young"- Die within the first 5 minutes of the life of the character.
"F***ing Hostile"- Kill the Guide when you have the Voodoo Doll in your inventory.
"God Is Dead?"- Have everyone in the server killed by the Wall of Flesh.
"Shedding Skin"- After creating a full armor set, create a second set of a higher tier and store the first set away.
"The Clairvoyant"- Buy the Crystal Ball and use it.
"Mr. Crowley"- Find and equip the Star Cloak.
"Die With Your Boots On"- Die while having either the Spectre, Hermes, or Rocket boots equipped.
"Goddam Electric" or "Ride the Lightning"- Make a functioning electrical device that uses at least 200 wire and can be activated.
"The Loneliness of the Long Distance Runner"- Make a skybridge spanning the entire horizontal length of the map.
"Show No Mercy" or "Angel of Death"- Kill 5 players in a row in a PVP match.
"Caught Somewhere in Time"- While in a multiplayer server, have the host change the in-game time from the console.
"Raining Blood"- Have everyone in the server (with at least three other players) die within one minute.
"The Song Remains the Same"- Buy a Music Box from the Wizard.
"Cleanse the Soul"- Reduce the spread of Corruption in a world to less than 2%.
"ABCDEath"- Create at least one of the letter/number statues at the heavy work bench.
"Waiting for the Sun"- Wear a Sun Charm in an active accessory slot for the duration of an entire night.
"Clash with Reality"- Get hit with the Confused debuff while in control of a Gravitation Potion.
"Brave New World"- Spawn a brand new character into a brand new world.
"Praise of Death"- Fail to defeat Skeletron before the morning and be killed by his attack.
"Nothin' to Lose"- Have all of your NPCs killed by a boss before killing the boss itself.
"Bats in the Belfry"- Hang at least two Bat Banners and Hellbat Banners in the same valid housing.
"The Art of Shredding"- Acquire the Axe from Plantera.
"Black Serenade"- Die while affected by the Blackout debuff.
"Rusty Cage"- Kill three Rusty Armored Bones with the same attack.
"Outshined"- Equip at least 4 different light-producing items or potions at once. (Shine potion, Mining Helmet, etc.)
"Funland at the Beach"- Set your spawn point within an Ocean biome.
"Glory Ride"- Attain your first rideable mount.
"Back in the Village"- Use a Recall potion.
"Floods"- successfully create Obsidian in the Underworld.
"This Love"- Use the Love Potion on an NPC.
"I, Zombie"- Kill five Zombies in a row with the Zombie Arm.
"The Mob Rules"- Be in a server with the maximum number of 8 players (yourself and 7 others).
"Eat your Heart Out"- Consume your first Life Fruit.
"The Final Command"- Kill an enemy from the grave.
"Black Hole Sun"- Survive a Solar Eclipse.
"Sweet Leaf"- Grow at least 4 different herbs in the same valid housing.
"Overlove"- Give Heart Crystals or Life Fruit to another player in multiplayer.
"March of the Fire Ants"- Conjure at least 5 active minions at once.
"Land of Confusion"- Create Hallowed and Corruption biomes directly side-by-side.
"Seven Faces"- Craft 7 helmets of different materials.
"Love, Hate, Love"- Switch your team in Multiplayer.
"Rime of the Ancient Mariner"- Defeat your first Pirate Invasion.
"I am Ahab"- Wear the full Sailor vanity suit.
"Battery"- Find a Lizahrd power cell.
"Dinosaur Vacume" [sic]- Find the Amber Mosquito from silt/slush.
"Buried Alive"- Suffocate from standing under silt/slush/sand.
"Legion of the Lost"- Hang each skeleton-related banner within the same valid housing.
"Dead Skin Mask"- Acquire a vanity mask from killing a Boss.
"Paranoid"- Try to run away from the Horrified debuff.
"Fight for your Right"- Have the Party Girl move into your world.