this post will be updated as I find more websites to add! please check with the original before reblogging to see if there’s an updated version, and message me with more suggestions if you have them!!
for general use
myspace.com - yes, it still exists, i’m just as surprised as you
soup.io - very similar to tumblr, plus it can import your tumblr blog
twitter.com - allows posting both text and photos in sets, allows retweets
livejournal.com - still an option, but questionably safe for fandom
wordpress.com - old and well-established, often considered the default
geared towards artists and photographers
deviantart.com - huge community, allows posting art + sorting into folders
furaffinity.net - similar to DA but for furries, easy to display commish info
instagram.com - photo and video posts, excellent tag search
piczel.tv - allows both streaming and posting art / photosets to a gallery
pixiv.net - huge anime art community, allows livestreaming
paid platforms
patreon.com - subscription-based access to many diff types of content
pillowfort.io - still in beta, but should function almost identically to tumblr
typepad.com - similar to wordpress but with reblogging and a dash
ways to save your current tumblr posts
use the wayback machine! you do have to archive each page of your blog individually but once you do all the content, including media, will be saved exactly as it was at the moment you archived it.
wordpress and soup both allow you to directly import whole tumblr blogs, and if i recall correctly it’s something both dreamwidth and pillowfort have said they are working on.
if you have some knowledge of computers you can try this github solution which uses a python script to download your whole blog to your computer.
even if you don’t know anything about programming or the command line
they give a very good beginners tutorial on how to use it so you should still give it a shot!
