https://www.unrealengine.com/marketplace/en-US/product/channel-machine
Channel Machine is a powerful and easy-to-use tool that allows you to pack different types of texture data into the color channels of an RGBA image. This way, you can save memory, bandwidth and performance by replacing three to four textures with one.
Channel Machine is also free and open source, so you can customize it to suit your needs by forking the repo on https://github.com/Kranox21/ChannelMachine