I have made a repository cataloguing tools like this: https://github.com/dbohdan/structured-text-tools.
APPlet Idea: an app that picks a random bookmark from your saves and sends you a reminder to click it and read it... and schedule when you want to see it - like every 7AM send me a link from my bookmarks. Set an alarm for 15 minutes to get me back on schedule.
I also discovered pawk on it which looks interesting, I made a somewhat related tool [1] which is probably out of scope for your list, but can be used in some of the same ways [2] and may of of interest nonetheless.
[1] https://github.com/elesiuta/pyxargs
[2] cat /etc/hosts | pyxargs -d \n --im json --pre "d={}" --post "print(dumps(d))" --py "d['{}'.split()[0]] = '{}'.split()[1]"