It's so weird that I always come on these boards and someone is talking about the exact thing I am thinking about.
I was just about to look for an online timer for schedule blocking (where you do one task at a time for work to increase efficiency, like the opposite of multitasking).
I actually have a physical gymboss. I didn't think of trying that.
I'll go check out the online version as well. What was the url for the one you found, Mom418?