>>29633625here is an image i've compiled of suspicious empty lots.
there are 6 pretty clear ones. the last two are not very clear but being near a pokecenter seems to be a strong indicator. i think it's possible that the graveyard could end up being a ghost type gym with an unconventional design. although there is also a sandy plot across from the pokecenter in the graveyard town. the western farm town doesn't seem to have any obvious open lots but between the pokecenter there and the one north of it i feel like there is a high probability that a gym will be located in that area. maybe it will be a floating gym located in the water features to the west?