For those downvoting the above poster, this probably wasn't a sarcastic quip - Tumblr really does plan to federate with the rest of the fediverse.

https://techcrunch.com/2022/11/21/tumblr-to-add-support-for-...

I'm guessing some might have downvoted because I mentioned paid providers. As in letting you pay them to run a Mastodon instance. While the above poster seems to have read my "and more are sure to come" as more options in general rather than more paid options. But I didn't downvote as I agree, the promise of Tumblr support is a big deal and will be a good option for a lot of people.

I know that's not what you meant but Tumblr is not free like your friendly neighborhood Mastodon instance or a foundation instance, it's for profit and paid for by advertisers and via paid features.