The Fediverse is more than just Mastodon! 
If you like to share photos you might want to check out @pixelfed, an Instagram-style photo sharing network on the Fediverse.
You can find out more and sign up at:
https://pixelfed.org
PixelFed uses the same federation protocol as Mastodon, which means Mastodon users can follow people on PixelFed and vice versa. You can try following a PixelFed account right now such as @Iancylkowski or @JoseMel or @connyduck
You can use PixelFed through a web browser, and there are also free open Android apps like @PixelDroid and FediLab (@apps).
If you love books, the best part of the Fediverse is probably @bookwyrm, a GoodReads-style social reading network.
More info and sites to sign up on are at:
Because it uses the same ActivityPub protocol that powers the rest of the Fediverse, you can follow BookWyrm accounts from Mastodon etc.
For example, the lead developer of BookWyrm has an account at @mouse
#Fediverse #FediTips #BookWyrm #Books #Book #Literature #Novels #Fiction #NonFiction #Reading #GoodReads #Alternatives
@firefly Hi, die Instanz betreibe ich, kann dir gern nen Invite schicken :)
@firefly @bookwyrm @mouse
I don't know any I'm afraid :(
Maybe you could email the administrator of wyrms.de and ask them? Their email address is at the bottom of their site's front page.