I’d feel like a complete poser if I didn’t recommend this. Besides my phone, my keys, and navy Uniqlo Supima Cotton Boxer Briefs (also highly rec!), a black Sharpie is the most commonly used thing in my life. It’s really the only writing instrument I use. Illustrations, notes, vandalism, to-do lists, they all get the felt tip treatment. I’d sign checks with them too, if I could. Might actually start doing that so my landlord can’t cash them.