Welcome to Geekhack!
You will find the measurements of the switches on the official sites for them:
•
https://www.cherrymx.de/en/dev.html•
http://matias.ca/switches/quiet/blueprints/?p=1But it is missing info on the stabilisers, so I attach a file which include them.
Alps switches often use the same stabilisers as for Cherry MX.
You can also find lots of footprints on Github, but most of them for the free EDA tool KiCad.
KiCad uses text-based formats so the measurements should be readable just by clicking the files, albeit not easily decipherable.
Among the footprints you could find are several solutions for combining Cherry MX and Alps, as well as a few different choices for how wide the solder pads should be. Some footprints you could find are symmetric - for making split keyboards with the same PCB design for both sides, and allow the switches to be soldered onto either side.
There are also footprints for Kailh sockets. (the copycats use the same measurements AFAIK)