Here's my list:
Archmage: Score a critical hit of 125 or higher with magic damage
Eagle-eye: Score a critical hit of 125 or higher with ranged damage
Blademaster: Score a critical hit of 125 or higher with melee damage
Conjurer: Score a hit of 50 or higher with a summoned minion
Archon: Deal 1,000,000 total magic damage
Paragon: Deal 1,000,000 total melee damage
Sniper: Deal 1,000,000 total ranged damage
Summoner: Deal 1,000,000 total summon damage
Purist: Kill the wall of flesh with 2500 or less prior damage dealt with each of 3 damage types. (IE: Pick 1 damage type and use it almost exclusively)
Explorer: Uncover 10% of the map in a large world
Armored: equip 5 trinkets at once with the 'warding' modifier
Vicious: equip 5 trinkets at once with the 'menacing' modifier
Lucky: equip 5 trinkets at once with the 'lucky' modifier
Energized: equip 5 trinkets at once with the 'arcane' modifier
A Step Up: obtain an item of tier-3 (orange) rarity
The World Waker: obtain an item of tier-5 (pink) rarity
I Have the Power!: obtain an item of maximum (cyan) rarity
Peasant: obtain a silver coin
A Middle-Class Lifestyle: obtain a gold coin
The One Percent: obtain a platinum coin
Investment Portfolio: obtain 25 platinum coins
Mogul: obtain 50 platinum coins
Midas: obtain a full stack of 100 platinum coins
The Impossible Achievement: Achieve 0.0% corruption on a large world during hard mode
Mile-High Club: Fall 5280 feet and survive
Curator: Obtain a total of 50 unique paintings
The Tables Have Turned: Summon and kill the Eye of Cthulu 10 times within 60 seconds.
Masochist: Summon and kill Skeletron Prime, The Twins, and The Destroyer within 5 minutes.
Rarer than You Might Think: Obtain a Slime Staff
All in the Family: Kill one of each type of slime
Et tu?: Kill the Queen Bee with the Bee Gun
By Fire be Purged!: Slay the Wall of Flesh with a Sunfury or Flamelash
You're Not Fooling Me: Kill 5 Mimics
Eclipsed: Survive a solar eclipse (from event start to night-time without dying)
Alchemist: Have 10 active potion buffs simultaneously
What are the Odds of that?: Score 5 critical hits in a row
I'm sure I could come up with many more, but hey, there's quite a few.