OK after testing Intel HD 530 on the ASUS Maximus VIII Hero with success, I tested the Gigabyte Z170X-UD5-TH. It appears as if we'll have to do some work on the Z170X-UD5-TH to make it work.
With Gigabyte Z170X-UD5-TH:
If I use Inject Intel = No I get black screen on HDMI port, which is the only graphics port besides the Thunderbolt 3 ports. If I Inject Intel = Yes, I can access the desktop, however there is no acceleration.
Bottom line- looks like we'll have to come up with some patches in order for some graphics port layouts to function correctly.
EDIT: Patching the framebuffer works- for the Gigabyte Z170X-UD5-TH, here is the patch to use in Clover's KextstoPatch section. It will replace the unused Port 0x0 with 0x7.
Code:
<dict> <key>Comment</key>
<string>Intel HD 530 - Port 7 as HDMI</string>
<key>Find</key>
<data>
/wAAAAEAAAAgAAAA
</data>
<key>Name</key>
<string>AppleIntelSKLGraphicsFramebuffer</string>
<key>Replace</key>
<data>
AwYKAAAIAACHAQAA
</data>
</dict>
Thanks to ammulder for the patch info!