It depends on your budget
I'm using an aukey keyboard that was 50 bucks and have been pretty happy with it
More expensive ones have better features like better switches, wireless, keys for macros, palm rest, etc.
The best mechanical keyboard ever made was the IBM Model M. I have a Model M keyboard that I got in 1986, it still works as if brand new, A company called Unicomp has the rights to the Model M and sells the Model m on their website. Unicomp