Hint #1:
Instead of placing a toolbox/chest of storage drawers directly on the workbench/shelf/roller cabinet top, put down two lengths of 2x4 and place the object on those. This creates an area under the object that can store flattish items. It's like getting an extra drawer for free. Putting sliding trays* in this space makes it even more drawer-like.
Hint #2:
We all allow "stuff" to accumulate on the workbench which we then need to move when we need to use the whole bench space. I solved this by covering that area of the bench with trays*. Now, when I need the space, it's easy to pick up the tray and its contents rather than having to handle each item separately. Of course, if you're one of those folks whose bench is always operating theater clean, feel free to ignore my idea. :-)
*Sources for trays:
Craft stores, eg Michaels, sell unfinished wooden trays that work well for lighter items
Rectangular cake baking pans work well
Cafeteria trays work well for larger spaces
There are innumerable varieties of plastic kitchen drawer organizers sold
If all else fails a sheet of plywood with a wood trim fence glued around the outer edge is easy to make
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