Based on this product's specifications, here are some alternatives and similar models
Battery Riff Analog for iPhone 6 Plus — Li‑Ion 2915 mAh, model RF-616-0770
Summary description:
Replacement Li‑Ion battery Riff Analog RF-616-0770 for iPhone 6 Plus with 2915 mAh capacity. Designed as a direct replacement to restore device runtime, it fits the original battery compartment and provides standard voltage and capacity for everyday use. Suitable for users wanting to replace a worn battery to regain longer screen-on time and stable operation.