I'm a happy user and big fan of the BaBo Organizer System from Willi3D . This is a custom insert that fits his Drawer Modul 60 perfectly.
It has a slot for a 80x80mm Sticky-Note block, a large section for pens and markers, and an extra section for anything else. On one version, the extra section is one big space, and on the other, it's split in half. There are two build plates - one with each version.
My insert matches the original dimensions of the BaBo Organizer and occupies a 6x5 grid.