I can’t live without my Nextcloud + Email server. Having all my personal files, contacts, email, calendar, and other personal information immediately accessible synced and backed up with a single app on any device or platform I want to use, is a dream come true, and I get to do it without any Big Tech, avoiding their lock-in and privacy invasion and without any fees or limits beyond my own hardware.

OpenVPN is how I can access it from anywhere in the world, so that gets an honorable mention too.