Zubat. Nothing is আরো annoying than having to go through a cave where there are Zubats and আপনি run out of repels.
Other than Zubat, I would have to say the roaming পোকেমন like the legendary bird trio. Having to track down the roaming পোকেমন is so annoying. আপনি can't even trap them with Mean Look since they'll always find a way to escape the battle.
As for the most annoying trainer pokémon, it's definitely Whitney's Miltank.
i'd say psyduck. he waddles around with a big-a** headache, আপনি can't do anything about it until it gets to the point where he uses a special সরানো for no reason!