Available four chars domains with results in the WayBack Machine

As always, you can verify availability at time of your visit even using the domains' checker in the sidebar.
All of this domains are available at time of this post.

szvv.net
3mri.net
mc-s.net
zyit.net
gdsd.net
cmd8.com
51wq.net
jnna.net
llzh.net
ct98.com