I was poking around Pokemon Home for awhile and happened to come across an old gem I had sitting around collecting dust for awhile - a shiny Metagross that I'm... not entirely sure how I came by but it's one of my old favorites nonetheless and I would love to feature it in a decent-ish team. Only problem is, I've kinda been out of the battling crowd for a while so I'm a bit rusty and am having some difficulty making up my mind for Metagross's partners.
Metagross is a great pick! So, are you looking to make a singles or doubles team? I'll list an idea for both, and just see what suits you best!
Singles:
Clefable is and will remain a monster in OU, so a strong steel type in Metagross who deals massive damage is a great way to break through a tank like that. Pokemon like Garchomp will favor getting rid of Clefable, so immediately that's one great pairing. You also have the ability to slot Metagross onto a sand team with the likes of Tyranitar and Excadrill.
Doubles:
Much of the same applies for Doubles, but Metagross now doesn't fear common stat lowering factors like Intimidate thanks to Clear Body, making it a very scary lead depending on the opponent's team. Pair it with Sand and it works great. Metagross can absolutely destroy Hail teams like Aurorus + Arctovish, Abomasnow etc. Kyurem is also going to be a common threat so having a Pokemon like Metagross might be a good option as it's currently not all that popular in usage. Other pairings could include general healing support in Chansey, Stall in Toxapex / Clefable, or full offensive with Garchomp and similar Pokemon. Metagross can fit with a lot of Pokemon.