I waited until Ep 11 aired to search for more hashtags, but production has been stingy the past several seasons about showing us clue cards.
So far we have (personal guesses in parentheses):
Leg 1 ?
Leg 2 #WalledCity
Leg 3 #catacombs
Leg 4 #jetstream
Leg 5 ?
Leg 6 #cascade
Leg 7 ?
Leg 8 ?
Leg 9 ? (#gateway)
Leg 10 ? (#stairway)
Leg 11 ? (#Silicon Valley)