I'm late to the party, but I'll compensate by posting 2 things.
1. [Zircon][zircon] is a text gui library I have been working on for a few years in my spare time, although I haven't contributed much to it lately. It also comes with a tutorial in which I implement a simple roguelike game ([Caves of Zircon](caves-of-zircon)).
2. This is more recent (in fact I haven't finished it yet): I have been working on a toolkit in the last few weeks that includes a scheduler, an event bus and a state machine library ([Cobalt](cobalt-ts)). Using these in conjuncion you can easily implement a workflow engine (that's what I'm gonna use this for). The interesting part is that it is implemented by using functional programming. Feel free to check it out if you need something like it (permissive license).
[zircon]: https://github.com/Hexworks/zircon [caves-of-zircon]: https://hexworks.org/posts/tutorials/2018/12/04/how-to-make-... [cobalt-ts]: https://github.com/Hexworks/cobalt-ts/blob/master/libs/hexwo...