There aren't that many mechanical keyboard switches on the market. Cherry and Kailh switches are by far the most ubiquitous, but there are several others that you'll bump into, as well. Greetech and TTC are two switch makers that we've seen on shipping products recently, and some keyboard OEMs have also begun crafting their own, including Logitech G's Romer switches, EpicGear's EG switches and Razer's Green (and Orange) switches.
Tackling Misconceptions
Of the above, few are as misunderstood as Razer's Green switches. It's a common misconception that they're just rebranded Kailh switches, but that is not the case. It is true that Kailh (Kaihua Electronics) is one of the manufacturers of the Razer Green switch, but Razer has them made to its own specifications.
That is to say, they are not identical to any Kailh switch.
The Razer Green switches even run on different production lines than Kailh switches. Further, Kailh is not the only manufacturer to produce the Razer Green switch. Razer will not divulge who any other manufacturing partners are, but Kaihua Electronics is not the sole supplier.