[Enrique]

Brains and intestine are common meat things in tacos, so I have tasted them. I like brains, but I don't like intestines (although intestines are way more popular).
I have eaten the eye of a fish (it tasted like calcium).
I have eaten the coagulated blood (this is called "morcilla" in spanish and it is commonly eaten in Argentina).
I am not sure now, but I think I have eaten testicles too. This is another dish which is not uncommon to eat in a taco. If I have eaten this, it was a long time ago.
One of my favorite things to eat, is the tongue. Whenever a foreign friend visits my hometown in Mexico, I make them taste tongue. Most people love it.