Ha! I’ll be odd duck out:
Primary is a hydrapak flux 1L: it’s light and stands up when full, but packs down to be tiny.
Flexible bottles get an upgrade. The Flux is shaped like a hard bottle, compresses like a softflask, and cuts weight by 50%. Topped with a dust cover and twist-drink nozzle for grab-and-go hydration, plus a bail handle to keep hydration secure in your hand or on your pack. The Flux stands...
hydrapak.com
I also use smart water bottles, which are admittedly a bit lighter than the flux bottle.