Nextcloud

Nextcloud is the file service you run on your own server, and the interface wears that openness. The Files view is a familiar list with sharing icons and per-item permission menus, but the defining trait is the top app launcher: a grid where storage sits beside calendar, contacts, talk, and dozens of admin-installed modules, so the product is whatever you bolt on. Sharing is granular, with link passwords, expiry, and federated shares across other Nextcloud instances. The trade-off is that the experience depends on the host. A well-tuned server feels fast and integrated; a default install can feel sluggish and visually dated, with feature density that overwhelms newcomers. It's the most configurable, least opinionated surface in the category, for better and worse.