The Anniversary Map Pack Add-on for Halo: Reach has 7 achievements worth 250 gamerscore.
Anniversary: Perform a Beat Down on an enemy player while using the Jetpack during a matchmade game.
Anniversary: Run over 5 people with a vehicle in a matchmade game.
Anniversary: Stick and kill the flag carrier with a Plasma Grenade in a matchmade game.
Anniversary: Infect 3 players in a single round in a matchmade Infection game.
Anniversary: Kill an enemy with their own Plasma Grenade that is stuck to you in a matchmade game.
Anniversary: Get 3 headshot kills in a row in a matchmade game.
Anniversary: Capture 10 skulls at once in a matchmade Headhunter game.