Newer keyboards (such as in the 90's and 2000's) mostly use a membrane and a rubbery button pad underneath the keys. The membrane and rubbery gums or pads are arguably not as precise as the old heavy keyboards that had individual switches per each key. 

Some older keyboards after the switch based ones had separate individual springs and plastic things that look like bullet shells per each key, but it still has a membrane which the plastic bullet shell pieces hit.

One can find an old keyboard by noting that it "weighs a tonne" at a used or second hand store. I have never found one or really looked for one, but if I see one I will buy one and test (and clean) it. 

There are some keyboards on the market that claim to be more precise and accurate. 

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You can still buy switch keyboards from 
*** http://www.pckeyboard.com/
*  who purchased the BucklingSwitch technology from IBM and designed USB and wireless models

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The cheapest 8-bit computers, like the Atari 400 and TimexSinclair 1000, had completely flat keyboards, much like microwaves have today.  Does that count?  The Atari 400 had only ridges bordering the keys, but the Timex avoided such luxuries to hit that magic $99 price point. 

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CategoryKeyboard