Homepage: https://play.google.com/store/apps/details?id=com.kroegerama.wear.mooncalc
Has a number of complications to add to your own watchface:
• Moon phase (Percent)
• Moon phase (w/ description)
• Small Image
• Large Image (can be used as wallpaper, if your watchface supports this)
• Moonrise and moonset
Comes with a Moon-Tile. A view, you can put next to your watchface.