Knife blocks commonly come in a plain wooden look. It is very easy and possible to turn this plain knife block into something colorful like your crayons. So, you can start to make the holes for crayons and then paint the whole body of the knife block. Doodling is also a great thing to do and later you can color it by using your crayons. This would be one of the most colorful DIY crayon holder ideas.
Meanwhile, if you are a rather advanced painter or crafter, you can turn a knife block into something more useful. You can install a hook to hold brushes and equipment for painting other than crayons. Feel free to paint the block with colors you like. If you do not want to paint, you can simply put some patterned tapes to decor the block.
On the other hand, if you do not have a knife block but still want to make a crayon holder, you can put several wooden sticks together and gather it inside a glass until it is full. Later, you can stick your crayons on it and simply pull it when you need to use them. This one is pretty cheap and easy to make. You just need to invest in glass and wooden sticks. It is always fun to make things that you interact with every day and one of them is from the DIY crayon holder ideas.
image source : pinterest.com