How to crop a custom card?

I was wondering how you crop your players out, or any app suggestions

I always use this website and than crop the leftovers with any background remover app.

https://burner.bonanza.com

if you search for a player on google and type "png" after the players name (for example "kobe bryant png") automattically cropped pics will show up

Fotoflexer.com

thanks yours is helpful 

what would be the best background crop website???