I have drawer systems that hold sliding wire baskets. I like this system as they come in different width and heights so it’s easy to customize for your space. I bought 5 single height drawers and one that is double height (serger thread)
The top drawers are just the right height for EMB spools. I had dry erase board cut to fit inside each drawer approx 20 x20 inches. Then hot glued golf tees in a grid to hold the threads. Each drawer holds 81 spools of EMB thread. I like this method as a drawer slides out and i can see the color needed.
I’ve used thread boxes for storage which works ok too.
Serger thread is in the bottom drawer stored in a similar method.