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Good enough gym squad?
C/SB Mewtwo
DT/O Dragonite
DT/DM Salamence
FS/SA Moltres
DB/DC Latios
BP/MM Metagross
These were picked with the resources provided by the DPS/TDO chart, (Chose top DPS picks with solid TDO, above 400) and what Pokemon I have available. Latios is in there because it makes a good low motivation sweeper, more so than other picks such as Smack Down Ttar.
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It's for gyms that DON'T have the big 4 in there, and instead have other things like Crobat, Venusaur, Milotic, Muk, Gardevoir, etc. People in my area love to make Machamps pretty much useless. Most Pokemon are hit neutrally or super effectively by at least one of those generalists, and it's better than matching attacker with defender. Also saves time so you don't need to switch.