One of the new bits coming out of this years WWDC (World Wide Developers Conference) is a Pride watch face. Vertical rainbow stripes move in and out of the field in 4 patterns. Two complications are included.
There is a hack to get it now* or just wait a few hours until after today's WWDC18 keynote address beginning at 10am Pacific.
*Change the date/time to after the keynote on your iPhone but going to Settings/General/Date & Time. Open the Watch app on your iPhone and voila! there's the new watch face. Add it to your watch. Check your watch for the Pride watch face and after it appears, change your iPhone Date & Time back to current (or set to Automatic)