AppManager is a GTK/Libadwaita developed desktop utility in Vala that makes installing and uninstalling AppImages on Linux desktop painless. It supports both SquashFS and DwarFS AppImage formats, features a seamless background auto-update process, and leverages zsync delta updates for efficient bandwidth usage. Double-click any .AppImage to open a macOS-style drag-and-drop window, just drag to install and AppManager will move the app, wire up desktop entries, and copy icons.
Appman works really well for managing appimages for me. It works like a package manager so “appman install app name” to install and “appman update” to update everything. It also runs at user level so no sudo required. It is CLI only though.