Grim is a command-line utility to take screenshots of wayland desktops.
Works great with slurp.
Requires scdoc

Example usage

Screenshoot all outputs:

grim

Screenshoot a specific output:

grim -o DP-1

Screenshoot a region:

grim -g "10,20 300x400"

Select a region and screenshoot it:

grim -g "$(slurp)"

Use a custom filename:

grim $(xdg-user-dir PICTURES)/$(date +'%s_grim.png')

Screenshoot and copy to clipboard:

grim - | wl-copy