I have downloaded the newest Cura Slicer Software as appimage and wanted to start it through my gnome favourites. To do so you need to create a .desktop file that refers to the appimage
vim ~/.local/share/applications/cura.desktop
and add
[Desktop Entry]
Name=Cura
Comment=Cura Slicer
Exec=/home/apunkt/Downloads/Ultimaker_Cura-4.11.0.AppImage
Icon=Acetino2
Terminal=false
Type=Application
Categories=Printer;
To change the icon you can choose any icon that is stored under
/usr/share/icons
just by naming it.