YSK: Mastodon bots work here too— there IS a remindme bot already!
Why YSK: I've seen several commenters asking if there were specific bots such as RemindMe
However, there are so many bots already on mastodon that will federate with us! Check out botsin.space, a masto-instance specifically made for hosting bots
Just tag @remindme@mstdn.social and say the time after (I recommend you not do it on this post unless you have an actual reason though as it could spam their servers)
This is insanely cool... I don't know why it never occurred to me that bots on other platforms could work here due to federation, but it makes so much sense. Thanks for sharing!
I also love the idea that we can have "bot instances" (as mentioned by OP) so an instance can decide if they want most bots or not. Not sure if communities themselves can exercise that kind of control but that would be amazing as well.
Add that to the rapidly growing lists of things that are improved on a decentralized platform!