For starters, they sell all kinds of meat, including entire pigs.
A Spanish claim to fame is their "Jamon." Which is basically cured ham. Its delicious and you can find it everywhere... they have loins hanging in all the markets and grocery store for available for purchase.
You can find everything at the market, including things that are traditionally available in the States, but it usually is a little different here. For example, if you buy a chicken, odds are it still has a head on it...