Here's an article I saw with a few other options. Some considerations in addition to appearance are how much water you want it to hold, whether you want it insulated to keep water cold and how easy it is to clean. Since you're using it for spinning weight isn't really an issue. The 7 Best Bike Water Bottles in 2020
The 26 fl. oz. Salsa Gravel Stories Purist water bottle delivers clean, fresh-tasting liquids at a high flow rate to slake your thirst when riding trails and roads. Why sip when you can chug? Available at REI, 100% Satisfaction Guaranteed.
Insulated and with a high-flow valve, the Co-op Cycles Insulated water bottle is designed to quench all thirsts—staying cool thanks to an insulating layer—when you're riding on warm days. Available at REI, 100% Satisfaction Guaranteed.
Both have the right amount of pliability when squeezed and generous water flow. Salsa offers what appears to be the same purist insulated bottle but with better graphics at $24. I didn't think the picture was worth the extra $, though. It's on the REI website if you're interested.