• Tri-bike behind-the-saddle holders.
• Fork mounts (A friend uses these on his long distance gravel grinder.)
• Handlebar holders, once popular in European road races (Google for pix from before the 1970s). Some triathlon and endurance riders still use these with drinking tubes.
• Frame bag, with narrower elongated bottles and drinking tubes.
• Collapsible reusable Mylar water pouches.
• Jersey pockets.

I may do the jersey pocket thing myself next long ride. I ran out of water Saturday. Weather was cool and overcast for August, since we're at the far outside reach of Hurricane Harvey. But I still underestimated my water intake because I was pushing harder on climbs. Fortunately family fishing at a nearby lake had a spare bottle of water. I was on the verge of dehydration and feel some of the effects today -- headachey, etc.

I always use a saddle bag for necessities so I don't really make much use of jersey pockets. Maybe a cell phone in the leftmost pocket, sunglasses and reading glasses in the right, spare bandanna and shop rag in the middle for wiping sweat. But next long ride I'll carry a spare disposable water bottle in a jersey pocket. The disposable bottles can be crushed and collapsed so they're easy to tote to the next available trash can. I also have a collapsible reusable Mylar water pouch. Prepped it for Saturday's ride, freezing it, but neglected to bring it along.