If we change the code a bit,

data MyAction = A1 Word8 | A2 Word16

a,b :: Get MyAction 
a = A1 <$> getWord8
b = A2 <$> getWord16be

listOfActions :: [Get MyAction] 
listOfActions = [a,b,a]

Now, we know how to execute the list of actions, and get the output as list. Using the following guys:

sequence :: Monad m => [m a] -> m [a]
runGet :: Get a -> ByteString -> a

Best,
Ozgur