All requirements met - HDMI 2.0, HDCP 2.2 & Intel SGX are here. Please note that the boards without the word "confirmed" were not tested yet. The 100 series MBs probably do not support HDR. Other motherboards with HDMI 1.4 may partially work too (without HDR). UHD BD playback via DisplayPort is untested, but Intel suggests it is possible.
ASRock Fatal1ty Z370 Gaming ITX/ac (UHD BD compatibility confirmed by flashback8)
ASRock Fatal1ty Z270 Gaming ITX/ac (UHD BD compatibility confirmed by CyberLink; download HDCP key from ASRock support page)
ASRock Fatal1ty Z170 Gaming ITX/ac (UHD BD compatibility confirmed by nilsman; Kaby Lake support since BIOS P7.10)
ASUS Z270 WS (UHD BD compatibility confirmed by yungtruth84 at forum.redfox.bz)
ASUS Z170 Premium (Kaby Lake support since BIOS 3007)
ASUS Z170 Deluxe (Kaby Lake support since BIOS 3007)
Biostar Z270GT9 (update BIOS to version Z27AF222 or later)
Biostar Z270GT8 (update BIOS to version Z27BF407 or later)
Gigabyte Z370N WIFI (UHD BD compatibility confirmed by Pioneer)
Gigabyte Aorus Z270X Gaming 9 (UHD BD compatibility confirmed by Pioneer; update BIOS to version F3 or later)
Gigabyte Aorus Z270X Gaming 8 (UHD BD compatibility confirmed by me; update BIOS to version F4 or later)
Supermicro C7Z270-PG (download SGX utility from Supermicro support page)
Supermicro C7Z270-CG (UHD BD compatibility confirmed by Steiger Dynamics; download SGX utility from Supermicro support page)