User blog comment:Gracey91/Achievements - By Smulder/@comment-4246239-20110919181036

Let's see...

An achievement for touching lava (while not under the influence of an Obsidian Skin potion) and surviving

An achievement for looting a treasure chest from a Floating Island

An achievement for getting a grappling hook

An achievement for looting one or more Shadow Chests in a single world's Underworld

An achievement for looting multiple Locked Chests in a single world's Dungeon

An achievement for looting a Jungle Shrine's treasure chest

An achievement for discovering an ocean

An achievement for discovering both oceans

An achievement for digging out 5000 or more Ebonstone blocks

An achievement for attracting each NPC to your town

An achievement for killing the Guide (possibly with a Guide Voodoo Doll)

An achievement for reaching the very top of your world

An achievement for reaching the very bottom of your world

That's about all that I can think of for the moment.