For my garage I used a combination of:
- Re-used junky Canadian Tire cabinets the previous owners installed in my House's Laundry Room (Right front), where I keep all my fluids/cleaners etc so they don't fall off the sides (Right front)
- Some Slot-rail shelves like what cunninglinguist posted (Right rear), cut down the cabinet doors from above to use as the actual shelves.
- Heavy duty shelf brackets with 1" Plywood on top for really heavy stuff like my cylinder heads & tire chains (above the tool boxes on the left)