Hyperkey
Turning Caps Lock into a fifth modifier
One toggle to enable, one optional secondary mapping for tap-vs-hold — the entire UI.
A free menu-bar app that rebinds Caps Lock to a hyper-modifier — when held, it fires ⌘⌥⌃⇧ together. The result is an entire shortcut namespace with zero conflicts against any app’s existing keybindings.
The hyper-key trick has lived inside Karabiner configurations for a decade. Hyperkey skips the JSON. Pair it with Raycast, BetterTouchTool, or the built-in Shortcuts app to bind Hyper+T → Terminal, Hyper+B → Browser, Hyper+anything to anything you do often.
Free, ~4 MB, runs at zero CPU. macOS 12+.