I put an old winch handle holder in the engine compartment to hold a replacement water pump/alternator belt and the wrenches needed for replacement
speaking of winch handle holders... it is very easy to make nice winch handle holders using a piece of pvc pipe..
heat the pipe in the oven on 250degrees and then place it between two pieces of plywood to create an oval shape to the pipe.... and hold or brace it until it cools.... then cut it to length, drill holes for mounting, and sand the cuts smooth.. THEN, paint it white.. or the color of your choice, and it will look great for years.... attach it wherever you need a holder...
the paint seals the pvc so it doesnt stain and/or turn yellowish as it ages....
for a holder in the engine compartment, or anywhere it wont be seen, you can take a piece of pvc tube of the length and diameter you want, and put a cap on one end.... then drill holes to mount the "holder" wherever you need a holder.... you can fix it with either a cap or a thread in cap if you need to keep it from ever spilling its contents.
the larger pvc caps, sized accordingly, can be attached anywhere a catch tray or drink holder is wanted.... like this one I made to replace my failed binnacle compass.