Countering Excadrill
Gardevoir can switch in, trace your Sand Rush and burn you.
Gardevoir has inferior Base Speed, so Exca, very likely, still has the first shot. However, that notion brings up another counter to Sand Rush Exca's rampage: Trick Room.
Doubled Speed means you move slower in Trick Room. Bronzong is bulky enough to throw one up, allowing slow Pokemon to get their revenge on the Sand Rushing bully. This makes the field of counters a wide open free-for-all:
-Bulky and slow(-ish) Water Types with Sandstorm protection like Slowbro/king with Leftovers, Quagsire, Swampert, Seismitoad, and Carracosta
-EQ-immune Steel Types like Skarmory, Magnet Rise Metagross, Magnet Rise Magnezone, Levitate Bronzong
-Sandstorm immune slow-runners like Rampardos, Rhyperior, Steelix, Camerupt, Torterra, Golurk, Magic Guard Clefable, Magic Guard Reuniclus, Cloud Nine Lickilicky, and Cloud Nine-taria
In a Trick Room situation, Excadrill is extra-screwed. The problem is that many of Exca's potential allies are also mentioned in there. Having low Speed, most of Exca's Rock, Ground, and/or Steel Type partners can turn Trick Room into
their advantage and stall it out. Hippowdon loves the flipped Speed with its Base 47, as does Tyranitar with its Base 61.