Hi there,
long time WLED user and fan here.
I’ve been away from the project for some time and I’m still diggin through all the new features…
So, first things first: respect and thanks to all the devs working on this project!
There might even be one or two merged PRs from me somewhere in the commit history 
In the early days I made a feature request to have something like timed effects for eg. notifications which was difficult at the time because of limited preset storage.
Looking at the current design and features it seems all the bits and pieces are there now, so I’d like to renew/redraw my request:
It would be a cool feature if the playlist had switch to save the current state, play the playlist and then return to the saved state, eg. by setting "end": 0 in JSON API.
Greetings
recliq