I've made an app that makes it possible to schedule a post in Lemmy at an arbitrary time. It's available at https://schedule.lemmings.world and can be used by people from any instance.
The creator of the tool is the admin of lemmings.world, and the tool is hosted at schedule.lemmings.world. So, if you have a user at lemmings.world, you can use this tool without having to trust a third-party.
If you don't have a user there, you can create a user in that instance for the purpose of creating scheduled posts. Removing the need to trust two parties rather than one.
And, of course, since the source code is open anyone else can attach this to their own instance! Pretty cool.
I would like to make a list at some point with several community integrations and ask my instance's users whether they would like some of them installed into the instance. This application will definitely go on that list! I do need to take into consideration how many resources each of the apps consume, to make sure I don't bloat my server. But this one seems quite light. Is it?