Our company is required same thing.

Plesk team must implement SAN certificate multiple domains or sub-domains in single certificate. This is the alternative option for wildcard

If you have a lot of subdomains, you may want to combine them into a single certificate, up to a limit of 100 Names per Certificate. Combined with the above limit, that means you can issue certificates containing up to 2,000 unique subdomains per week. A certificate with multiple names is often called a SAN certificate, or sometimes a UCC certificate.

letsencrypt allow this as mentioned on https://letsencrypt.org/docs/rate-limits/

Plesk team should implement this feature as soon as possible

+1 It would be very usefull to be able to add custom subdomains when requesting a Let's Encrypt certificate.

Since Startcom/StartSSL is going down the bad way, we need a replacement asap. Let's Encrypt solves this generally, but it's not yet possible to manage multi-subdomain certs in plesk.

Please make it possible to add multiple subdomains to create the mailserver certificate.
Either let the admin choose on their own or define at least the follwoing default subdomains to be included into the host certificate.

mail.my-servername.de
pop.my-servername.de
pop3.my-servername.de
imap.my-servername.de
imap4.my-servername.de
smtp.my-servername.de

Thanks!

letsencrypt for webmail.domain.tld, mail.domain.tld ftp.domain.tld etc

+1
at least WEBMAIL !

For me, subdomains working with lets encrypt extension, but not domain aliases
https://plesk.uservoice.com/forums/184549-feature-suggestions/suggestions/15013254-let-s-encrypt-add-domain-aliases

Definitly needed for technical subdomains like pop, smtp, imap, webmail and so on ...

The Number for Lets Encrypt Certificates comes not from Plesk, the Certificate is limited to one domain additional the www subdomain by lets encrypt self. This is the feature for this certificate. Wildcard is the same problem.

would also be great for webmail sub-domain

This would be wonderful, primarily because of the rate limit currently imposed.

That would be awesome and would simplify the work with a wordpress mulitsite with subdomains enabled and a wildcard setup in plesk! I guess that is a common situation?