It's impossible to get all the type matches. Even with full dual-type Pokemon, it'll still can't cover all elements.
i don't mean for one whole team of six.
i mean to get the medals quickly you can only get two at a time (not counting dual type solo pokemon that'll get three medals) so a team with dual types will get you the medals of said types. like grass and poison etc. i am going to use roserade, vileplume, victreebel, venusaur as main 4 and maybe add more.
i want a list that will give combinations that'll get 8 different dual types plus the leftover type. that'll mean only 9 goes through the elite four (ten if not counting the one only pokemon). --- Lights will guide you home