0809 Melmetal

Thunder Shock is the one and only fast move available to Melmetal. 

Rock Slide is Melmetal's primary move of choice. It's cheap, spammy, and has great offensive coverage. Double Iron Bash is an alternate option, providing STAB and even more spamminess at the expense of some coverage. Pair either move with Superpower for a big hit against other Steel-types.

Thunderbolt, Flash Cannon, and Hyper Beam are all outclassed by those moves, although Flash Cannon can be used to land a surprise, extremely heavy hit against Zacian. If you were to use Rock Slide/Thunderbolt, you should use Probopass instead. Flash Cannon and Hyper Beam just aren't that valuable.

Melmetal held an incredibly strong niche early in PvP. However, with the release of more and more powerful Steel-types, it has fallen out of favor. Still, though, the combination of Rock Slide and Superpower gives it solid coverage against relevant meta Pokémon. Other Pokémon can just do Melmetal better in open format.

Melmetal is better in Ultra League than Great League. It's a powerful Steel-type, often functioning like Budget Registeel. However, unlike Registeel, Melmetal can hit Pokémon like Charizard and Gyarados for Super Effective damage with Rock Slide.

Melmetal's Steel-typing and solid bulk allows it to be a stalwart backbone to many teams in the Master League. It primarily functions as an answer to Dialga, Lugia, and Togekiss. Melmetal is also no slouch offensively, having slightly higher ATK than Togekiss and Giratina-O, alongside extremely spammy charge moves that have great coverage combined. Although Melmetal may not exactly win some of these matchups, it can threaten Ho-Oh, Yveltal, Excadrill, Snorlax, and Zarude super effectively, allowing it to function as a check when combined with its spamminess. Melmetal's excellent bulk and numerous resistances grants it a lot of freedom when it comes to overcharging, and can easily store charge moves while switching out to search for better targets to unleash them on.

Melmetal's primary counters are Ground-types like Groudon and both formes of Landorus. It also struggles heavily against Giratina-O, who simply deals much more damage to it thanks to Shadow Claw and Shadow Ball being very powerful moves. Zacian is also a major threat as it threatens both Melmetal and the Dragon- or Dark-type Pokemon that Melmetal likes to partner with.