witch dugeons have.....

[Bunny_Parasol]

Kecleon Stalls?

 

[Scepgatr]

Mt. Blaze
Frosty Forest
Mt. Faraway
Western Cave
Northern Range
Pitfall Valley
Wish Cave
Desert Region
Wyvern Hill
Joyous Tower
Purity Forest
Remains Island

 

[Caterpie Master]

And Magma Cavern too.
Not many times, but sometimes you can encounter a stall there.

 

[diamondboy]

my first stall was in mt. blaze

 

[penngrade6]

I think its random.