I used to be deep into the personal knowledge management tar pit. Most of it was wasted time. Here are the few things in it that I actually regularly use and get something out of. These are just simple zim-wiki text files that I update and skim through a couple times a month:

- Idea list: Ideas for art or other projects that I'd like to try some day. I'm occasionally adding new ones and I've started work on old ones I've added that finally piqued my interest.

- Gift idea list: Things friends and family may hint at wanting or outright say they want in casual conversation. I add stuff to this list then buy it for birthdays, Christmas, etc. Can get some real nice surprises for people when they only mention things in passing and you happen to catch it.

- Book list: Just a wish list of books. Occasionally I'll buy a few to add to my personal library and cross them off the list.

Just understand that most of the personal knowledge management stuff is a waste of time. It's a bunch of feel-good busywork that's typically sold to you first as a cheap idea, then sold to you as products like Roam Research, Obsidian, etc. Can't really beat simple lists in text files or on paper. I even like physical notebooks that you go through and keep a hand-written index in the back of. Forces you to think and revisit stuff.