I would refer you to Blue Jean and Belden WEB sites. Not only do they have specs, but they are real and tested to them.
HDMI cables are the biggest pile of junk I have found. After many false starts, I went Blue Jean and no problems since. Only a little bit more and I know they meet spec.
Ethernet, again, the Belden cables meet spec. I am sure others do, but who knows. I believe for anything outside a data canter, any old crap Ethernet cable is more than good enough but that encroaches on the "religion" part of audio.
USB I found by testing, bad ones and good ones. Esoteric ones are just good ones. A good one works, a bad one can pick up a lot of noise. ( loopback tests on a Focusrite Scarlett) Every free one that came with cheap DACs were in the "bad" category except one from JDS. I only kept them for phone charging and my label printer.
USB has the widest options for signal format. Optical breaks a ground loop if you have one. I prefer USB as the DAC can run WASAPI in asynchronous mode, so the better clock in the DAC is in control. My main music server is USB only anyway. I tested Toslink on my desk and did not hear any difference. Don't know what advantage coax/PCM gives you other than distance as Toslink is limited to about 11 feet. With the exception of noise passed through a poor input stage, at the digital level, bits are bits. Once inside a DAC, that is a whole different thing what you do with those bits.
With the possible exception of Ethernet, shorter is always better. I'll match my Amazon 6 inch RCA "well made" cables to any uber-esoteric 1M cables. My main system I have a 1 foot USB cable. No RCA is longer than 1M.
For balanced XLR wire, it seems the Mogami cable is quite respected. I have not looked but I think they post real data.
Do check out the video " for everyone" I mentioned in an earlier posting and it will help with specs.