Free Domain Name Graveyard
"Not everything buried is actually dead. For many, the past is alive." ― Louise Penny, Bury Your Dead
As detailed in domain vs. subdomain, free domains are sometimes less reliable. The domain owner may, at any time, decide to forbid new subdomain registrations, with active subdomains shut off as they expire, or they may instantly shut the service off altogether, selling the short domain name for traffic to the highest bidder, or just forget about / lose interest in renewing it, all of which result in you losing your precious subdomain you've been so eagerly developing and promoting all around the web. Unfortunately, this happens.
Here is a list of free domain providers that, for various reasons, didn't pass the rough test of time; their review pages memorialized:
If you held subdomains with any of these services, our sympathies extend to you. Try again.