Thoughts on adding a preview/example of what an effect looks like on the effect buttons in the app? It would contain what’s shown on this wiki page:
I would be happy to build a pull request to add this if it’s something that would get integrated.
GUI have a preview for effects in real time.
The Peek button at the top of the wled interface kind of does what you seek to peek at 
Yes but that requires actually changing the lights as you are testing various combinations. Not a big deal I guess. Was thinking if they showed on each button it would be a lot faster to pick something similar to what you were looking for.
I’ve been wanting a layout visualizer that would allow you to place segments with number of lights each and all the settings applied and then you can really build your layout seeing how each segment will behave applying effects and palettes.
Basically the ability to send the data stream to a live view that can display just what the lights would do. 