An amusing accessory for larger tripods is the triangular nylon fabric "shelf" with rim, attached to tripod by three leather straps. $35.00, Manfrotto. Park a water bottle, lenses you are swapping out, flashlight, whatever on the shelf. I use mine for astrophotography, to park drive battery pack, flashlight, cell phone running Sky Safari, lens caps, etc.
Once you have a hook, consider saving the cut at top only mesh bag from some oranges - compact, you can put rocks in and hang via mesh off hook. Or, if your waterbottle has a loop or carabiner, hang water, at 1.65 lb. per full bottle.
