Amazon.com: NEWDERY Battery Case for Google Pixel 4a 5G, 4700mAh Slim Portable Protective Extended Charging Case with Full Edge Protection, Rechargeable Battery Charger Case for Pixel 4a 5G(Not for Pixel 4a) :
OEM BN30 Replacement Battery For Xiaomi Redmi 4A 3120 mAh + Tools | eBay
Google Pixel 4a Battery Replacement - iFixit Repair Guide