If you dont know what a pseudo legendary is, then firstly they are all below in the poll, and secondly in the main series they are all three stage evolution Pokemon with 600 BST. I.e strong.
Either way: here is the poll:
Kommo-o is the best because it would be the most relevant to our current meta. Fighting/Dragon would be perfect. Also, not a lot of people have good fairy types meaning that it will be more useful. Goodra is also really good because it is a pure Dragon type meaning only 2 weaknesses. Also, it has great moves that could beat Dragonite out of the park. Metagross is good because it and Tyranitar have Mega Evolutions which boosts their ranking.
I only know pokemon from Pokemon Go, so still 3 generations for me
I choose Tyranitar because it hasgood moveset in Dark and Rock perspective
It also has more use against the raid bosses so far compare with other pseudo legendary
Garchomp hands down
Was so amazing in its debut it had to be banned (and was the first non-legendary non-mythical Pokemon to be banned after Wynaut and Wobuffet, which were only banned because they could cause endless battles), continues to be a versatile Pokemon thorough the generations, and even got a Mega (but sadly, its a crappy one, maybe it could get a second one like Charizard?)
In GO its a direct upgrade to Dragonite, so no discussion here either