Calibre-Web is a web app providing a clean interface for browsing, reading and downloading eBooks using an existing Calibre database.

Prowlarr is a indexer manager/proxy built on the popular arr .net/reactjs base stack to integrate with your various PVR apps. Prowlarr supports both Torrent Trackers and Usenet Indexers. It integrates seamlessly with Sonarr, Radarr, Lidarr, and Readarr offering complete management of your indexers with no per app Indexer setup required (we do it all).

The qBittorrent project aims to provide an open-source software alternative to µTorrent.

Locally hosted web application that allows you to perform various operations on PDF files, such as splitting, merging, adding images and many more!

Jackett works as a proxy server: it translates queries from apps (Sonarr, Radarr, SickRage, CouchPotato, Mylar, DuckieTV, etc) into tracker-site-specific http queries, parses the html response, then sends results back to the requesting software.

Synology is a popular NAS appliance