How to List Installed Packages Using Snap

I’d like to get a list of packages installed manually by snap and be able to find out whether a foobar package was installed manually by system installer.

For example:

$ snap list
Name                 Version                     Rev   Tracking         Publisher     Notes
canonical-livepatch  9.5.5                       95    latest/stable    canonical✓    -
core                 16-2.45.2                   9665  latest/stable    canonical✓    core
core18               20200707                    1880  latest/stable    canonical✓    base
discord              0.0.10                      109   latest/stable    snapcrafters  -
gnome-3-28-1804      3.28.0-17-gde3d74c.de3d74c  128   latest/stable    canonical✓    -
gnome-3-34-1804      0+git.3009fc7               36    latest/stable/…  canonical✓    -
gtk-common-themes    0.1-36-gc75f853             1506  latest/stable/…  canonical✓    -
ripgrep              12.1.0                      9     latest/stable    icey          classic
simplenote           1.20.0                      368   latest/stable    snapcrafters  -
slack                4.7.0                       25    latest/stable    slack✓        classic
snap-store           3.36.0-80-g208fd61          467   latest/stable/…  canonical✓    -
snapd                2.45.2                      8542  latest/stable    canonical✓    snapd
zoom-client          5.1.422789.0705             92    latest/stable    ogra          -

Here, core, core18 were not manually installed by me (at least not explicitly), so my try was:

$ snap list | grep -v Publisher | grep -v canonical | awk '{print $1}' | tr 'n' ' '
discord ripgrep simplenote slack zoom-client

However, I’m not sure if this is the right way to exclude automatically installed packages. Is there any neat way of doing that from the command line?