KANTO: Pewter and Cerulean Gyms fits well. If we count a game-inexistent volcano, Cinnabar Gym fit too.
JOHTO: Azalea, Goldenrod, Ecruteak and Blackthorn Gyms are the ones that we can say that have theme coincidences.
HOENN: Dewford doesn't fit.
SINNOH: Veilstone, Hearthome and Canalave doesn't fit at all.
UNOVA: As stated by
>>40269053, only Striation don't fit (it can't) and Icirrus only fit in Winter. Aspertia, Virbank and Humilau Gyms fits well, too.
KALOS: Shalour and Coumarine Gyms doesn't fit at all.
If we count the Alolan Island Challenge, Mina's trial is the only that doesn't really scream's it type.
We conclude that every region, without exception, has a Gym that don't fit the theme of its city.
So please don't complain with Allister/Bea Gym.