What cable companies make the best cables and sell them directly?

Requisite Audio

I got a silver Digital coax SFDIF from them and I was pleasantly surprised. 

Very reasonably priced. 

Found these guys. Audio Sensibility.

Zenwavesudio too

Both direct and easy to deal with

And there’s Morrow Audio too. 

Check out Audiomica cables, I came from Purist and Cardas Beyond and now a full loom of Audiomica and couldn't be happier. I didn't pay retail bought from importer at good discount. Do some research on Audiomica lots of reviews but not much talk.

Have had great experience with Audio Sensibility if you’re up for comparing some cryo stuff, he’s made a number of special request cables for me over the years and is great to deal with. Also does trade ups. 

https://audiosensibility.com/blog/

Check out Darwin cables. They do what cables should: get out of the way and impose as little of their own character on the signal. I use them for my ICs and SCs. Vendors at audio shows use their cables to show off their stereo gear. I’ve worked my way up their line and with each step, it got better.

They have some of, if not the lowest capacitance around. They are fast, articulate, tight and textured with no smearing or homogenizing of the sound. They also employ four different stereo set ups to ensure across the board performance that doesn't favor any particular type of gear.

Check out their Specials section to see what discounts you can get to get a taste. Tony and Bill are great to deal with and if you like, just talk shop.

All the best,
Nonoise