FireRed elite four team:
Electrode
Parasect
Pidgeot
Kanghaskhan
Charizard
Kabutops
I used Pidgeot in Gen II. Fair warning, his movepool isn't that great.
I love Parasect for some reason. Unfortunately I already have Venusaur and using Parasect makes a bigass Fire hole.
Also since you told me I seem to enjoy tanks, I find I really do enjoy tanking more than other things.
So I like Omastar more than Kabutops because,
1. Omastar tanks better
2. Kabutops is too mainstream
Kangaskhan is severely underrated. So is Electrode.
Charizard can be as complex or simple as you like, but with a little thought into a Charizard build, he's a kickass murderer.