Any starch will work. I've used taro, cassava, ube yams, kabocha, plantains, and chestnuts. They do need to be boiled or baked but I can do this all in advance on a lazy weekend. The ones with lower water content will need more egg or other liquid. Savory seasonings and work nicely too.
Lots of: urban hiking, cycling, sprinting
Lots of: fresh meat, seafood, eggs, organs, tubers, starch fruits, vegetables, meat fat, dairy fat, oil fruits
Some: cured meat, dairy protein, sweet fruits, rice, pulses, tree nuts, oil seeds
Minimal: soy, refined proteins, sugar, liquid carbohydrate, grains, refined oils, peanuts