The A26 also gets a bigger 6.7-inch display (up from 6.5") and improved materials. You will find Gorilla Glass Victus+ protective sheets on the front and back. Additionally, the A26 gets proper IP67 ingress protection, far better than standard splash-proofed phones in the same price bracket.
The Pixel 6 Pro comes in a more compact box, now that a charger is no longer included. Underneath the handset in the box, you'll find a USB-C to USB-C charging cable, SIM-eject tool, documentation, and a 'Quick Transfer Adapter'. This lets you connect a USB-A cable into the Pixel to transfer data from another Android or iOS device.