After many years of searching for a battery case for my Nikon cameras, this is the best one I found in the market so far, best suited for traveling, that could store and charge 2 batteries, and also store and read SD cards.
Nikon: https://s.click.aliexpress.com/e/_DDC6RuR
Canon: https://s.click.aliexpress.com/e/_DBJiLSx
Sony (NP-FZ100): https://s.click.aliexpress.com/e/_DBk77Wj
Sony (NP-FW50): https://s.click.aliexpress.com/e/_DljXkk7
Sony (NP-BN1): https://s.click.aliexpress.com/e/_DCAIcXZ
Panasonic (DMW-BLC12): https://s.click.aliexpress.com/e/_DkZpgNl