Here is the full list of all 12 Catan achievements worth 200 gamerscore. It takes around 15-20 hours to unlock all of the achievements on Xbox 360.
You collected 1000 VP's.
You collected 500 VP's.
You collected 250 VP's.
You won Largest Army 10 times.
You won Longest Road 10 times.
You invited someone to play Catan.
You beat three Hard AIs in Catan.
You collected 100 VP's.
You beat three Moderate AIs in Catan.
You collected 25 Victory Points.
You acquired 100 resource cards.
You built a settlement in Catan.