My quilt group (Telequilters) had a challenge whereby we all made the same 3 yard pattern, but each using different fabrics.
We all had to donate 1 yard of a fabric we had in our collection. Those donations were then swapped anonymously within the group, and we then had to add on other fabric from our own collection to go with the donated fabric.
The colour combination here is much 'louder' than what I usually used, but having to add from our own collection was a good change to push my colour boundaries.