Steam ROM Manager is a tool to add ROMs as Non-Steam Game Shortcuts.
Introduction
EmuDeck installs Steam ROM Manager https://github.com/SteamGridDB/steam-rom-manager, which allows you to add your ROMs directly to your library. It can either be used as an alternative or in tandem with ES-DE (a frontend application to manage your ROMs.).
Steam ROM Manager's Website: https://github.com/SteamGridDB/steam-rom-manager
Steam ROM Manager sources art from SteamGridDB: https://www.steamgriddb.com/
Read the ES-DE page to learn more about ES-DE and how it can be used in tandem with Steam ROM Manager!