I almost always work with scraps but I find it more restful and satisfying if there is some sort of connection. Often, just using a consistent block can give this but I prefer coming up with some sort of colour scheme as well. All of these quilts were made from scraps and most of those scraps were in the format you're playing with. :-)
I'm currently working on a sort of colourblock approach - nothing much to show right now because it's just a mess of exploded scrap boxes but I'm hoping those boxes will close once I've used up some of the fabric. :-)
This video shows a different way of approaching GingerK's block as well.
https://www.youtube.com/watch?v=skTDNIDjFCA