You can install and use the Appimage Manager tool for consolidating, updating and upgrading all Appimages:
Add the repository:
sudo add-apt-repository ppa:appimagelauncher-team/stable
Update sources and install:
sudo apt update && sudo apt install appimagelauncher
Once installed, look in the app menu for AppimageLauncher Settings.
EDIT:
Suggested by @Maxwell-J is an app Bauh which can manage Snap, Flatpak and Appimages.
Bauh must be installed by PiP:
sudo apt install pip
Then use pip to install Bauh
sudo pip install bauh
This is qt based, so be warned, you will not be able to use your system theme on this appimage manager.
I tested it as well and it is promising, though I was unable to get it to select "appimages" as a file type to support. YMMV.
It still seems a Better alternative to some out there... And given a choice between appimagelauncher and Bauh, I would choose Bauh.
While I am at it...
I went seearching for more.
I found the best App Image manager tool I have tested so far:
This also will not use your system theme, but it comes default with a pleasant Dark Theme.
It behaved well and offered a lot of apps as AppImages. I had no trouble with it.
Its layout and appearance is similar to the Software store included with Zorin OS.
Its Preferences are rather spartan and meager. But for what it is, it does it well.