I'm looking for a method (or at least anything any wrote about this topic) which uses icons or symbols for note taking. So for example, I will be taking notes in class and want to "tag" certain things such as "idea", "key point", "good", "bad", etc. I find that coming up with symbols that are meaningful and easy to draw is hard to do. I was hoping that there is already a repository of such icons somewhere.
The reason I want icons rather than text tags is to make the notes more appealing and less verbose. That way when it comes time to study, I'm not just staring at a bunch of text and I can visually understand what many of the sections mean just by looking at the icons.
Some examples I have come up with:
- Light bulbs are easy to draw. I use them for new ideas.
- Crossed out arrow is used for "does not lead to" (or something along those lines), while an arrow can be used to mean "leads to".
- A home icon is used for homework (idea from OneNote, see below).
- I am currently looking for something to be used to represent good/bad. I was thinking of using a thumbs up/down image, but find it difficult to draw. Happy/sad faces, on the other hand, are easier to draw, but don't have clear meanings.
- Similar to how OneNote has three different colors for some of the icons, I can do the same with only one color of ink by having one shape not filled in, another filled in with dashed lines, and the third completely filled in.
I was thinking of getting ideas from Microsoft OneNote, but many of these icons are difficult to draw by hand:

I'm hoping someone has already come up with something like this so that I don't need to reinvent the wheel. Any ideas that can help?