TikTok:

• Loops

Facebook meets blogging:

• Friendica

Facebook meets blogging meets Apple iCloud/Google Cloud Services meets the nomadic identity that the ATmosphere has yet to prove to have:

• (streams)
• Forte

Facebook meets blogging meets Apple iCloud/Google Cloud Services meets the nomadic identity that the ATmosphere has yet to prove to have with a ton of other stuff on top:

• Hubzilla

Instagram:

• Pixelfed

Twitter:

• Mastodon
• Pleroma
• Akkoma
• Misskey
• Sharkey
• Iceshrimp
• CherryPick
• and a whole bunch more

Reddit, Hacker News:

• Lemmy
• Mbin
• PieFed

YouTube:

• PeerTube

Twitch:

• Owncast

SoundCloud:

• Funkwhale

BandCamp:

• Bandwagon

Medium:

• WriteFreely
• Plume (half-dead; devs recommend WriteFreely)

Tumblr:

• wafrn

Vkontakte:

• Smithereen

Goodreads:

• BookWyrm