I can't believe I hadn't come across this utility until now!
Bunch is a macOS automation tool that takes a folder of plain text files containing lists of apps and commands to launch and provides an easy-to-use menu for triggering them.
Bunch is developed by Brett Terpstra, a well-known and prolific automation aficionado for the Mac. From what I can tell, Bunch abstracts AppleScript, shell scripts and apps by making them available as simple, plain text directives which are easy to write and run from the macOS toolbar.
I've downloaded the latest stable version to play around with, and if I think it's worthwhile, I'll post a review.