With the inability to box or ship multiple items in one listing, I think it would be beneficial if we could group individual listings together into a collection / set.
The individual items are still available to purchase on their own; a collection just enables the customer to purchase matching items with 1 transaction, paying the collective amount of money for all of the items combined.
Perhaps an additional feature could enable us to set a % discount when purchasing a collection, giving a greater incentive for the customer to purchase the whole set.
Examples of where this may be needed are primarily building kits. Walls, fencing, hedges, corresponding landscape packages such as ivy sets or vegetation; things that need several pieces in order to be put together correctly. Other uses could be matching furniture assets, building collections, terrains, rocks.