Nextcloud is a suite of client-server software for creating and using file hosting services. Pretty much Dropbox. But it’s free and open-source! Anyone is allowed to install their own private server. The functionality of Nextcloud can also be extended in a number of ways by installing apps/add-ons/extensions/extracoolstuff. These are the ones I use to improve my Nextcloud experience both in the WebGUI and my mobile devices.
> Manage calendar events and sync it to your devices.
> Manage contacts and sync them to your devices.
> Kanban style organization tool.
> Dedicated gallery/grid with previews of all all media types supported by the Nextcloud installation.
> Extends the text editor with live preview for markdown files.
> Edit Mind Maps in the WebGUI.
> RSS/Atom feed aggregator. There’s also a nice news app on f-droid.
> Organize markdown notes using categories.
> View PDFs in the WebGUI.
> Common actions context menu when right clicking on files in the WebGUI.
> Organize tasks/subtasks/weekly tasks etc.