Team help

Hi everyone!

Im quite new to the game, just started playing last week and I’ve just defeated East. I was wondering if someone could help me come up with a sixth team member for my team!

By the end of the maingame im planning to have a team that looks like this:

Delta Venosaur

Mega Flygon


Delta Bisharp

Delta Haxorus

I know that Bisharp and Haxorus can be obtained before the postgame, so I was wondering if someone could recommend me a sixth team member that can also be caught before the postgame! Thanks in advance!