Would be great to have a thread-pool in here...

[mdbergmann]

...in order to avoid having X other thread pools from other libraries.

Could this be a candidate?

[sionescu]

Perhaps, although I'd like to see a comparison between the features of those other libraries, to see what makes sense as general-purpose.

[mdbergmann]

I came across this one as well, which ships with it's own thread-pool:
https://gitlab.com/ediethelm/trivial-timer.