Simple matrix frame you can use to encapsulate the quite common 8×8 module of 64 WS2812B LEDs.

The back side of the model contains holes to fit the caps between the LEDs nicely. Some adjustment of the side walls might be needed, tho, based on the actual millimetre board size after its factory cut.

It's a must have (together with a diffusion layer you need to put in front of it) to disperse the usually circular-looking LED light into real pixel-like shape. Combined with a lightweight micro-controller like ESP32-C3 SuperMini & a battery, it's definitely a nice WLED project for beginners! 👍

You can get the LED module pretty much everywhere, here's a sample AliExpress listing that I used recently.