Board: Ergodox EZ, with cherry MX Browns and XDA keycaps with a 36-key Colemak-DH layout.

Mods:

1. Plenty of foam in the case
2. Lubed switches
3. O-rings
4. Mounting putty
5. Painters tape over unused hot swap ports ... for now. I'll either switch to something black (even if it leaves a residue) or upgrade to a true 36 key board down the road.

The putty is admittedly a subtle effect, but not one I'd seen before. It had the greatest effect on the rattling space bar on my previous board. And, sculpting the putty to add weight to the keycaps (without sticking to the switch when bottoming out) was pretty tedious, but so is lubing.