Low-profile gasket-mounted mechanical keyboard, aluminium case, hot-swap POM switches. Now 119 USD because Flow 2 replaced it.

Three Macs, one monitor, one keyboard: the Advantage360's Mod keys switch keyboard and display together over Bluetooth and DDC. No KVM box needed.

Hyperkey is a free macOS utility that converts the Caps Lock key (or any modifier key) into a "hyper key" — all four modifiers combined (⌃⌥⌘⇧) — giving you an additional modifier for keyboard shortcuts in any app.

Superkey is a macOS utility by Ryan Hanson that enhances keyboard efficiency through OCR-based seek-and-click, hyperkey remapping, and power-user presets.

for reference