Must have apps for running your own personal media.
Updates:
May 20th, 2022: Replaced Mylar with Mylar3. Removed Cardigan due to discontinuation of development. May 17th, 2022: Removed CouchPotato since it has been officially discontinued and the github repo archived by the author. Added "Readarr" and "Requestrr" to media management and request management. May 16th, 2022: Added additional apps to the Honorable Mentions section. March 27, 2019: Added MediaElch for metadata editing, TagScanner for audio file metadata editing, and Emby as an alternative to Plex. December 3, 2018: Added Soundiiz for online music service playlist synchronization. July 30, 2018: Added Mylar and Ombi. July 28, 2018: Added Honorable Mentions section with other noteworthy media apps. July 11, 2018: Added cTiVo as a media downloader. June 18, 2018: Added a section for Search and Indexer utilities, which may utilized by the various Media Managers also listed below.
Requestrr is a chatbot used to simplify using services like Sonarr/Radarr/Ombi via the use of chat. Current platform is Discord only, but the bot was built around the ideology of quick adaptation for new features as well as new platforms.
Ombi is a front end user facing request system. It connects with your other media managers (CouchPotato, SickRage, SickGear, Sonarr, Lidarr, and Radarr, etc) to automate user requests and adding them into your media library managers.
MusicBrainz is a community music metadatabase that attempts to create a comprehensive music information site. You can use the MusicBrainz data either by browsing this web site, or you can access the data from a client program — for example, a CD player program can use...
Discogs is a crowdsourced music database and marketplace. Discover music, buy and sell music with collectors in the Marketplace in all physical formats.
Launched online in 1990 and a subsidiary of Amazon.com since 1998, IMDb is the world's most popular and authoritative source for movie, TV and celebrity content, designed to help fans explore the world of movies and shows and decide what to watch.
Track your TV shows and movies automatically with media integration and mobile check-ins. Discover new favorites and use the extensive API across platforms.
Metacritic's proprietary Metascore distills the opinions of the most respected critics writing online and in print to a single number.
Rotten Tomatoes and the Tomatometer score are the world’s most trusted recommendation resources for quality entertainment. As the leading online aggregator of movie and TV show reviews from critics, we provide fans with a comprehensive guide to what’s Fresh – and what’s Rotten –...
Media managers are programs designed to oversee the automation of your media collection. They take metadata for content you are interested in, track what you already have and what you still need, then watch indexes as content becomes available
#1 for Television series.
A fork of Sonarr that is targeted for Movies. It isn't yet perfect, but it is getting very close to being able to be a full on replacement for Couchpotato.
Lidarr is a music collection manager for downloading and organizing music libraries. It is a fork of Sonarr designed for music.
Downloads can happen through Usenet using 
SABnzbd or via BitTorrent—it's up to you. All you need to do is fill in the settings so things are handled the way you prefer. And wow, you can really fine-tune your preferences.
Currently the only option for music that comes close to functionality in terms of its equivilents in the television and movie categories.
Transferring playlists and favorites between various music platforms. With more than 40 platforms supported, we make it painless to manage your collection.
Music Playlist Synchronization between 20+ online music services.
Readarr is an ebook and audiobook collection manager for Usenet and BitTorrent users. It can monitor multiple RSS feeds for new books from your favorite authors and will grab, sort, and rename them. Note that only one type of a given book is supported.
Prowlarr is an indexer manager/proxy to integrate with your various PVR apps. Prowlarr supports management of both Torrent Trackers and Usenet Indexers. It integrates seamlessly with Lidarr, Mylar3, Radarr, Readarr, and Sonarr.
NZBHydra2 is a meta search for NZB indexers. It provides easy access to a number of raw and newznab based indexers. You can search all your indexers from one place and use it as indexer source for tools like Sonarr or CouchPotato.
An NZB indexer proxy which supports built in result deduplication, load balancing queries across multiple upstream servers, result caching, and nzb caching. Also can be used as a search engine directly and can send desired results to download managers.
Jackett works as a proxy server: it translates queries from apps 
Sonarr 
Radarr 
SickChill 
CouchPotato .
A torznab proxy which adds support for various bittorrent trackers to any media manager which supports the newznab API. Meaning any media manager which doesn't natively support a given bittorrent tracker for searching, can now be utilized indirectly through Jackett.
The most efficient usenet downloader. NZBGet is written in C++ and designed with performance in mind to achieve maximum download speed by using very little system resources.
NNTP binary client. NZBGet performs better than SABnzbd in my testing by a factor of 4:1, however does not have all the bells and whistles as SABnzbd. Meaning some downloads that may fail in NZBget don't fail in SABnzbd. Only negative is that article sets that have lots of missing articles on primary servers, will cause the queue to slow down due to the way the logic handles how and when articles are fetched. Meaning an article set that has a high number of missing articles can block your queue where as NZBGet's competitor, SABnzbd would begin simultaneously starting the next article set in queue, meaining you don't have idle bandwidth going to waste if using SABnzbd. That said, all things considered, I prefer NZBget over SABnzbd due to the massive performance difference on downloading, reassembly, and unpacking.
NNTP binary client. Uses more CPU than NZBGet but it is a time tested and proven client, and powers through circumstances where NZBGet may fail. SAB uses a non-blocking method of trying secondary servers for articles.
Transmission has the features you expect in a BitTorrent client: encryption, a web-based interface, peer exchange, UPnP and NAT-PMP port forwarding, web seed support, watch directories, tracker editing, global and per-torrent speed limits, and more.
Online storage and torrent client for direct torrent downloads, file management, and streaming to devices like iOS, Roku, Plex, and Android.
Need something to watch? We’re on it. Plex combines free movies & TV with the best free streaming services, so there’s always more to discover.
#1. My number one choice for media playback of any type. Integrated sharing, accessibility via real time conversion and streaming or raw file bitstreaming to the Plex app made for every platform on any device.
Open-source media player supporting Linux to iOS, highly customizable with plug-ins, supports 4K and diverse formats, privacy-centric and ad-free.
#2. My number two choice when you don't want to rely on any third party service.
Cross-platform, free media player supports multimedia files, DVDs, streaming, offers hardware acceleration, 4K, lossless audio, and more.
#3. A good go-to media player for opening and playing back one-off files.
Apps that are noteworthy.
Download videos from YouTube and over 1000 sites using a platform-independent command-line tool, requiring Python. Integration with other programs is possible.
Watcher is an automated movie NZB & Torrent searcher and snatcher. You can add a list of wanted movies and Watcher will automatically send the NZB or Torrent to your download client.
FlexGet is a multipurpose automation tool for all of your media Support for torrents, nzbs, podcasts, comics, TV, movies, RSS, HTML, CSV, and more.
OpenFLIXR Media Server is an all-in-one media server for automated downloading and serving media. Tools like CouchPotato, SickRage, Headphones and SABnzbd to download and Plex Media Server to bring everything to your screens.
Medusa is a fork of 
Sick Beard (similar to other forks such as SickChill and 
SickGear ). It allows for automatic television series monitoring of episode information off the...
Medusa is a TV episode manager with a focus on anime and handling the anime episode numbering scheme.
SickGear has proven the most reliable and stable TV fork of the great Sick-Beard to fully automate TV enjoyment with innovation.
A stable and well supported fork of SickBeard. SickBeard balances continued development with good testing and quality control. It's the safe choice when needing something more up to date than SickBeard but more stable than SickRage.
SickChill, previously SickRage, is a fork of Sick Beard to automatically download TV shows from usenet or torrents.
A fork from SickBeard with an active community and ongoing development.
Awesome PVR for usenet and torrents. Just fill in what you want to see and CouchPotato will add it to your "want to watch"-list. Every day it will search through multiple sources, looking for the best possible match.
Discontinued, but has some awesome features like adding subscriptions t to iTunes top movies, and auto updating these and submitting them to your media managers.
Sick Beard is a PVR for newsgroup users (with limited torrent support). It watches for new episodes of your favorite shows and when they are posted it downloads them, sorts and renames them, and optionally generates metadata for them. It currently supports NZBs.
The original PVR for TV episodes from usenet. From SickBeard came the forks SickRage, then later SickGear. SickBeard slowed development and became stale. SickRage picked up where SickBeard left off, and SickGear is a newer fork of SickRage with an emphasis in quality control on software testing and deployment.
cTiVo is a free Mac application to download shows from your TiVo (Roamio, Premiere, HD, S3 or S2 devices) and convert them to many popular formats and devices. Its goal is to be extremely simple to set up and use, but very flexible.
cTiVo grabs tv shows from your TiVo via your network, and can transcode them or simply place and organize them into a local or network folder. It can automatically delete the successfully transferred content off your TiVo keeping space available for more content.
Free e-book manager offering library management, multi-format conversion, syncing to devices, news download as e-books, built-in viewer, editor, and privacy.
Calibre-Web is a web app providing a clean interface for browsing, reading and downloading eBooks using an existing 
calibre database.
Calibre Web is a web UI to Calibre, a utility for automating book downloading and library management.
Emby, formerly Media Browser, is a media aggregator plugin for Media Center that takes your recorded, digital, or ripped media and presents it in a simple, easy to use interface. Emby prides itself on delivering a fast, intuitive, media rich experience for the whole family.
Mylar has been replaced by Mylar3, an updated version of Mylar coded in Python 3.
Comments
MediaPortal, MP3tag and MPTagThat deserve at least honorable mention!
this list is great
Awesome list! Keep up the good work and let us know if miss something with lists or if you have any feature requests and so on. We just added commenting as you notice when you read this :)