@michaelc I have 4 colours of uniball: black for main notes, red to flag action items, blue for odd ideas peripheral to the meeting I’m in and green for really weird stuff.

Mind you, the black gets less use now that I take meeting notes with a fountain pen and then transfer them to digital as needed.

I also have fine whiteboard markers and small white board cards for plotting or mapping, often by sticking them on the blackboard behind me.