A tag, giving back reading between 0 and 100 depending on current moon phase:
0/100 - full moon
1-24 - Waxing Crescent
25 - First Quarter
26-49 - Waxing Gibbous
50 - new moon
51-74 - Waning Gibbous
75 - Last Quarter
76-99 - Waning Crescent
Also, another tag that gives back the name of a current moon phase (as above) would be nice too.
yeah Mellin having the ability to sync to the Moon calendar will solve the issue. with out it, is complicated because the phases take 28 days which gets out off sync with the system Calendar. 
That wold have saved me so much time on this design : Vincent - Moonwalker - watch face for Apple Watch, Samsung Gear S3, Huawei Watch, and more - Facer
I’d say it should be from 0 to 180 or 0 to 360… but that’s a detail. Voting !
Do you have any idea how to add moon phase in a watch face just using the eight phases,so NOT the rotation, but a sequence of eight images?
In Facer creator I cannot find it…
Surprised this is still not a feature. Not even a tutorial I can find. Just some stuff for making a rotating dial. Really it should be a tag that is easy to use.