Shieldon and ProCase both make very nice leather wallet cases for both the S8 and S8+. The Shieldon is better for the S8, as the magnets keep the case closed with cards in the pockets. Neither company's S8+ cases stay closed if anything is in the pockets. That being said, the ProCase wallet's kickstand worked better, for me.
They're very similar and have nice flair. Both on Amazon, though the Shieldon was cheaper on their own website.