I saw a few desk organisers on Thingiverse, but none were quite right for me. So I designed this one from scratch. Perhaps it's perfect for you too?
Measures: 172mm wide x 100.5mm deep x 100mm high
Can hold standard sized post it notes (76x76mm). Business cards (lying horizontally up to 87mm long). Or put your phone in there (thanks to my girlfriend for pointing this out). Bunch of pens and whatever you want to throw in the tray. Also a little cavity tucked under the post it notes with a slight lip so that whatever is in there doesn't slide out if the organiser is knocked. Likewise, the tray also has a gradient at the front so it's easy to slide awkward objects out of it.
Design optimized for a 0.4mm nozzle with PLA, but anything will work. Super easy to print, no supports needed.
Would love to see pictures of yours printed with whatever you stick in it. Always appreciate comments too :)