ComicReader is a Plex Channel that allows you to serve comic book archives that are stored on your server.
Currently it supports CBZ, CBR, and CB7 comic archives. CBZ is supported natively, while CBR and CB7 require unrar and 7zip. See the Readme on github for details.
The channel doesn't use a database or metadata, it just acts like a file browser that starts at the directory you specify in the channels preferences.