Assuming you're looking for a key, not a keyer (most rigs have them built in) then Vibroplex and Bencher are the usual choices. Many more are available - for a lot of money. And there are some specialized keys, like those that plug into an Elecraft rig's front panel. But I advise staying away from cheap, gimmick keys. My own (key and keyer) are Nye Viking but they are no longer made and can only be found used.
Chris