AceAbove Kickstand Wallet Case
The AceAbove PU Leather Kickstand and Wallet Case is an all-in-one worth checking out. They claim it fits all G4 versions, including the leather variant, and their case is made out of a durable PU leather as well. It comes in black with red accents, or pink for the ladies.
This case folds around to completely protect the case, features a wallet area to hold three credit cards plus some cash, and the oragami-style flip cover for the screen folds back and doubles (or triples) as a kickstand.
Unlike some flip cases it has a durable button to close it tight so you won't lose anything from the wallet. It can be bulky especially once you add credit cards and cash, so keep that in mind.