Explorer - Find a Mushroom Island
Block Protector - Build an Iron Golem
Snowball Fight!! - Build a SnowMan
Swapper - Trade with a villager.
Trader - Trade with a villager 5 times.
Customer - Trade with a villager 10 times
Finders Keepers - Find a chest in a Abandoned Mineshaft.
Dungeoner - Destroy the mob spawner in a dungeon and raid all the chests.
Green Thumb - Use bonemeal to grow grass and flowers.
Astronaut - Build up to block 256.
Playin' Hardcore - Survive on Hardcore for 1 night.
Pro - Survive on Hardcore for 5 nights.
Music? - Make a skeleton kill a creeper and gain a music disc
Suggestion: How about adding Multiplayer Achievements? I also have some ideas for that:
Bow Battler: Kill another player using a bow.
Winner: Kill another player.
Warrior: Kill 5 players.
Assassin: Kill 10 players.
Whoops!: Hit another player off a cliff or into lava.
Licensed Driver - travel over 100 blocks by minecart or boat
Coffee-obsessed - go for 5 consecutive nights without sleeping
On the Run - go for 10 consecutive nights without sleeping
Ultimate Fan - make your pet dog kill 10 mobs
Get Creative!! - place 1,000 wood planks
Get your permit - crash 5 boats
Noob - Place Over 1000 Blocks of Dirt Or Gravel
Not Quite your Day - Die Over 10 Times in 1 Day
Enchanteer - Use Every Enchantment Once
Greifer - Use over 100 Tnt
Cooker - Make over 100 Cooked Meat
Wheatie - Make over 100 Bread
Matrix - Dodge 20 Arrows Shot From Skeletons
Team Kill - Watch a Mob Kill another Mob
The Pet Master - Tame a dog, a cat, and a horse
Trick of the Trade - Trade with villagers 20 times
Cheers! - Drink 20 potions
Indestructible - Wear full diamond armor
Bon Appetit - Make and eat every single food at least once
Death is just a state of mind - Hit dat respawn button.
Tailor-made - Dye a piece of leather armor.
Series of unfortunate events - Get combo'd in any way (Example: Taking blast damage from a creeper which sends you off a cliff dealing fall damage) Death is not a requirement.
Birth Control - Destroy a spawner cage.
Superior Spelunker - Mine 50 coal, 25 iron, 15 gold, 5 diamonds, find a dungeon (come within 15 blocks of a spawner) and find a mineshaft (come within 15 blocks of a natural-spawned rail), without rising back to sea level for a surface break in between.
Gonna buy me an island - Mine an emerald.
Some assembly required - Build an iron golem.
Arf Army - Have over 20 wolves tamed at once.
Kitty City - Have over 20 cats tamed at once.
I risked my life for this... - Receive a tool from a fallen monster with 15% durability or less left.
Sniper Joust: Kill a spider-jockey's skeleton with a bow and arrow while either on horseback, pigback, or riding in a minecart Requires: Sniper Duel
Now I've seen everything... : Slay the legendary Chicken Jockey! (Just the zom-baby part counts) Requires: Monster Hunter
It won't work here, genius... : Place a beacon in the Nether. Requires: Beaconator
Hell on Earth: Using either superflat presets or hacking the game, cause the nether biome to appear in the overworld. Requires: None. This achievement is always hidden until the game detects the player standing in a "Hell" biome while still in the overworld. Can be considered both an easter egg (if gotten through superflat presets) or being reprimanded for hacking nether chunks into the overworld.
A Sword Named "Anna": Rename an item with an Anvil Requires: Acquire Hardware
...And I shall call him "Bob": Name a passive or neutral mob with a nametag. (Pigmen, Endermen, and Neutral Spiders don't count.) Requires: A Sword Named "Anna"
Inversion!: Name a mob "Dinnerbone" or "Grumm" with a nametag and watch the magic happen. Requires: ...And I shall call him "Bob"
My Arch-Nemesis: Name a hostile mob with a nametag. Requires: ...And I shall call him "Bob"
...With a Herring!: Mine a wood block while holding any kind of fish. Requires: Delicious Fish
U.N. Owen was Sword?: Obtain a sword with 3 or more max-level sword enchantments. (Any combination of Sharpness V, Smite V, Bane of the Arthropods V, Knockback II, Fire Aspect II, or Looting III) Requires: Enchanter or Overkill, whichever seems better.
Harbinger of Death: Wipe out the entire population of a village because you're a sadist. (or let the zombies do it for you.) Requires: Time to Strike!
This wouldn't work. Minecraft saves achievements to worlds, and when you die in hardcore, you lose the world. Thus there would be no way to tack this.
Probably should have thought of that. Anyway, I came up with several new achievements and here they are:
Robin Hood: Kill 10 enemies with a bow
Katniss Everdeen: Kill 50 enemies with a bow
They Call Me Rambo: Kill 100 enemies with a bow
Now here's some trails off of existing achievements:
This achievement trail: Diamonds to you
Richie Rich: Give 5 diamonds to another player
Bill Gates: GIve 20 diamonds to another player
The Godfather: Give 50 diamonds to another player
Now for some nether based achievements:
Home Field Advantage: Kill a wither in the nether
Burning up: Get killed by a blaze
Roasting: Get killed by a blaze 5 times
Rotisserie: Get killed by a blaze 20 times
Family Barbecue: Get killed by a blaze 50 times
Hold on, we're going home: Leave the nether
Acne: Collect 64 nether wart while still in the nether
In the lava again: Die in lava while in the nether
Quartz collector: Collect 64 nether quartz
Now, for some completely random achievements:
Gold Rush: Collect 8 gold ingots
Pimp: Collect 20 gold ingots
Ooooo Shiny: Collect 50 gold ingots
Klondike Flashback: Collect 100 gold ingots
That was awkward: Accidentally kill a villager
I can't stop: Kill 5 villagers
Murderer: Kill 10 villagers
Serial Killer: Kill 20 villagers
Dexter: Kill 50 villagers
Hannibal Lector: Kill 100 villagers
Stone age: Obtain all stone tools
Iron Man: Obtain full iron armor and tools
The 6 Million Dollar Man: Obtain full diamond armor and tools
Rage Quit: On the respawn screen, click "Back To Title Screen"
Cheater Cheater Pumpkin Eater: Make a survival world with cheats enabled
And finally, A revision to my first achievement:
3rd time's the charm: Defeat the Ender Dragon on your 3rd try
Villager Talker - Open up a villager trading interface. Requires Taking Inventory.
Crop Finder - Get a carrot/potato. (From ground) - Requires Taking Inventory. (If possible, then either Villager Talker or Monster Hunter)
Villager Trader - Trade with a villager. Requires Villager Talker.
Baked Potato - Get a Baked Potato. (From Furnace) - Requires Crop Finder. (If possible, add Hot Topic as well)
Golden Carrot - Make a Golden Carrot. (From crafting table) - Requires Acquire Hardware.
GOLD!!!!! - Get a gold ingot. (From furnace) - Requires Acquire Hardware. Super Apple - Craft a Notch Apple. (From crafting table) - Requires GOLD!!!!! Enchant - Enchant something. Requires Enchanter. 1-hit-KO - Deal 10 hearts of damage in a single hit. Requires Overkill. Maxed Enchantment - Do a level 30 enchant. Requires [[That one that requires the bookshelf]]