fosstodon.org is one of the many independent Mastodon servers you can use to participate in the fediverse.
Fosstodon is an invite only Mastodon instance that is open to those who are interested in technology; particularly free & open source software.
If you wish to join, contact us for an invite.
@codemonkey@Tutanota Another one like that is https://mailinabox.email/ . It also gets you set up with calendar and contacts with nextcloud so you have a full pim suite going. And webmail