In India, Arabian Sea salt is the most common option. People following Satvik diet (on some days) use any rock salt, and Himalayan Rock salt is another common option in my area. It has lower sodium, so some people also use it for health purpose. It is pink in colour.
I also use Black Salt (I don't know its source) when I have to eat fruits. It has a slightly sour flavour and some vegans use it to give their dishes "egg" like taste.