Here are some more general achievement ideas, mostly intended to be humorous, for your consideration. Some of them obviously may not be feasible based on the what info the API gives you.
  • Telecommute/Work from home - Kill an enemy from 350+ meters
  • Breakfast Combo - Kill a fully loaded Sundy with AT mines.
  • Building a house - lay x bricks of C4
  • It's raining men - drop 11 people from your galaxy in x seconds
  • Spawn room hero - kill x enemies without leaving the spawn
  • Rebuttal - kill an enemy who has done more than 50% damage to you before you begin doing damage to them.
  • Delicious bacon - destroy/deploy x squad beacons
  • Really? - OHK(or be killed by) a teammate with a sniper rifle
  • Pacifist - fire x bullets without hitting anything
  • How many fingers? - Get concussed x number of times in y seconds
  • Is this your job? - play x hours in y time period
  • Gaben - In a given play session, on your third life, get 3 kills in a row, with three different weapons.
  • How hard is it to push a button? - Get killed by a vehicle you have stuck c4 to.
  • Live fast - get killed within x seconds of spawning y times in a row.
  • You have a gun, you know? - heal x amount/revive y number of people without doing any damage.
  • Let it go - Avenge yourself x number of times in a row.
  • Bullet Sponge - take x damage without respawning