I have been using Buzzkill for several years and I love it. That being said, I am very “audio focused” and love the fact that each type of notification can be set to have a different sound and vibration pattern. As far as visual settings, especially in relation to a LED, I did not see any settings that can directly affect those. However, there is an option to trigger a Tasker task which may be something you could use in setting up LED notifications. But I don’t currently use Tasker and cannot confirm this functionality.
In any case, good luck!
I have not used this functionality yet, but it does have a reminder option.