Glitch allows you to have multiple custom domains on a project but I think it would be cool to have wildcard domains.
Note: For anyone who does not know what a wild card is:
A wildcard DNS record is a record in a DNS zone that will match requests for non-existent domain names. A wildcard DNS record is specified by using a * as the leftmost label (part) of a domain name, e.g. *.example.com.
Also @TurboBiscuit said he was too lazy to make a feature request, so I made it for him.