i @turbine
For just a few datasets, toggle into Hidden tab in the history. Click on the eye icon to hide or unhide each dataset, or you can use the multi-select to hide/unhide in a batch.
More ways to transform the shape is covered in here. → Hands-on: Using dataset collections / Using dataset collections / Using Galaxy and Managing your Data
Tool panel → Collection Operations is where these tools are. Each has a little graphic to show what is happening but please ask if there is anything else and I’ll try to help.