LinkFlick

I built this because I got sick of re-pairing my Magic Keyboard and Mouse every time I moved between my MacBook and my work MacBook — different Apple IDs, so Universal Control was never going to work for me. LinkFlick just flicks them over Bluetooth instead. Hotkey, or tell Siri "flick devices," done. Menu bar app, customizable hotkey, and it nags you before your Magic Mouse battery dies. Still rough around the edges in places, but it works, and it's mine.