Clicky Univac magnetic switches • A HaaTa find from 1971, the switches from the Univac keyboard predate both the buckling spring and beam spring mechanism, and are clicky. Very clicky. It uses magnets to achieve the tactility and obnoxiously loud clickiness.
IBM buckling spring • The IBM buckling spring is a type of spring-based switch where the spring buckles outwards instead of compressing, and powers the famous IBM Model F and Model M keyboards.
Matias Click switch • The Matias Click switch is a clone of the Alps CM switch with a tactile leaf held loosely to allow it to click, manufactured by Matias Corporation primarily for its own keyboards.
Matias Quiet switch • The Matias Quiet switch is a clone of the Alps CM switch with a damped slider, manufactured by Matias Corporation primarily for its own keyboards.
Topre switch • Topre switches power the "Only one Made in Japan electrostatic capacitive non-contact type keyboard in the world".
And the Wingnut for Best keyboard switch 2013, as voted for by the members of deskthority, goes to...