On internet there is a lot of great designs for 3D printing. You can find almost everything on sites that covers 3D modeling and printing (like Thingiverse, My mini factory, Cults…)
LED strip for Ender3
Based on https://www.thingiverse.com/thing:3090287Webcam stand
https://www.thingiverse.com/thing:3147743Key hanger
https://www.thingiverse.com/thing:3167468USB organizer
https://www.thingiverse.com/thing:2375384Sanding block
https://www.thingiverse.com/thing:3671006Fast operation vise
https://www.thingiverse.com/thing:4563901Douglas airplane
https://www.thingiverse.com/thing:1597365Bell Huey
https://www.thingiverse.com/thing:3479128Airport tower
https://www.thingiverse.com/thing:3543410Cessna 172
based on https://www.thingiverse.com/thing:814319Space shuttle
https://www.thingiverse.com/thing:2825854Extruder knob for Ender 3
https://www.thingiverse.com/thing:3366468Cable clips
https://www.thingiverse.com/thing:2960375Sanding tools
https://www.myminifactory.com/object/3d-print-mini-sanding-tools-106028Storage box
based on https://www.thingiverse.com/thing:2805609Another storage box
based on https://www.myminifactory.com/object/3d-print-small-items-divided-storage-box-94254Filament guide Ender 3 Rain meter Vallejo paint organizer Airbus A318 Another Vallejo paint organizer Soldering station Spool winder Combination safe