Some modules & ideas that would be nice are
2.add on ports lightning/type C/micro/USB type A
3. Light bar/battery
4.Qi wireless charger transmitter/receiver/battery
5. Variable voltage output to power other devices
6. Velcro strap to keep modules together in case of drop. Thin and lightweight
7. Contacts for extra modules on both sides included click on magnetic covers for when contacts are not in use
The slim 5000mah battery bank might be a good platform to build off and possibly keep the modules a similar size magnetic/snap on . Keep up the good work kid. I'm very impressed with your interest and determination especially at such a young age. I really liked your original Moto mod type idea. A larger model based of the 20,000 would also be useful and desirable.