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I mean this was written on Jun 6 so of course garbodor was still in the tier (well it was in ZU but now NU), and frosslass was ZU but now NU, so I think just a few changes could make it work out.
Aggron is an incredible wall breaker in SS PU because thanks to it's access to Head Smash and rock head, it would destroy Charizard and doing a whole lot of damage to guzzlord if not a guaranteed KO. While it may have two x4 weaknesses to ground and fighting, Aggron will adapt. With a choice...