Yup, I use the Propel powder in single serving Mylar packets. Carry 'em in my seat bag. I prefer DripDrop ORS packets but those cost much more, $8-$10 per box of 6 or 8 packets, vs $3 for Propel. Propel is good enough for my needs.

I also sometimes carry MiO Mylar packets of energy boosters -- caffeine, B vitamins, sugar, stevia, etc. They're usually cheap at the local Kroger because they had a bunch in damaged boxes.

Sometimes I'll add creatine/BCAA powder from a big container at home, mostly on workout days including PT sessions and bike rides. I don't use creatine every day because it makes me pee more. An embarrassing hassle on a couple of bike rides before I caught on to the reason. Had to make half a dozen pit stops in 20-30 miles. On the plus side, it does seem to help with hard workouts, including interval training on the indoor trainer or nearby outdoor 5 mile circuit, close enough to home that I can dash home for bathroom breaks.