The one single power and connectivity kit needed in your laptop backpack.
① One +65W USB-C power charger
② One USB-C 2m/6ft cable with Power Delivery
③ One USB-C kit of adapters to old USB and Micro USB
④ One USB-C adapter to Apple Lightning
This kit: Powers your modern laptop through USB-C. Charges your phone through Lightning or USB-C. Charges eventual other devices on their old USB ports. Connects all devices to one another.
Portable batteries are obsolete. Instead, use your large and powerful laptop battery to charge your phone on the road.