Alright. These are the rules : You may only select one Pokemon per generation. And since there are 6 generations, in the end you will have 6 Pokemon ( obviously) , thus making it one whole team. No legendaries, No mega evolutions, but you can use pseudo legendaries. Here is my choice:
Arcanine
Crobat
Metagross
Garchomp
Zoroark
Greninja
Now you!
Arcanine
Crobat
Metagross
Garchomp
Zoroark
Greninja
Now you!