Hi Theodor - I don't have any experience with WIFI-compatible SKs, I just bought my D810 a few days ago. According to the camera manual by Heike Jasper, a professional photographer, she uses an Eye-Fi card which is plugged into a special USB card reader (also from Eye-Fi) and transmits the data directly to the tablet PC-phone. Check out Eye-Fi on the internet. I hope you find a good WLAN-compatible solution.
Greetings Stefan Schläpfer

Memory cards - In the filter options WLAN yes:
https://www.digitec.ch/de...

If you want to transfer RAW, then you should buy a Mobi Pro... actually, that's the best solution.

I would also recommend the SDHC Card Eye-Fi Mobi Pro 32GB Wi-Fi
https://www.brack.ch/sdhc-card-...

Thank you very much for the answer. Lightroom tethering does not solve the problem for me - I would like to transfer a photo from my NIKON D800 directly to my iPhone6.
Best regards Theodor Schmid

I can't judge that as I only have a small one and as I shoot in RAW it doesn't go far.
I would simply say that the card has to be fast enough, otherwise only the size plays a role for me.
But I have done the so-called "lightroom tethering" with a USB cable, which works fine.
Kind regards, Frank Uray