Moves
Slack Off is Slowpoke's most reliable recovery option and allows it to maintain its longevity. Scald is a powerful STAB move that can hit Fire-, Rock-, and Ground-types such as Ponyta, Onix, and Mudbray super effectively; it can also provide some utility by burning physical attackers to render them weak. Psychic is Slowpoke's secondary powerful STAB move, hitting common Poison- and Fighting-types like Mienfoo, Foongus, and Croagunk. Croagunk especially is an important target due to its ability to easily switch into Scald. Thunder Wave is an important utility move that Slowpoke has, and it can spread paralysis to cripple fast offensive Pokemon such as Abra; however, Slowpoke still cannot outspeed paralyzed 18 Speed Pokemon. Fire Blast is an alternative option as a powerful coverage move that hits Pawniard, Ferroseed, Alolan Sandshrew, Magnemite, and Snivy. Alternatively, Slowpoke can use Calm Mind on defensive cores or bulkier teams once Dark-types have been eliminated. It can set up to become more specially bulky and sweep opposing teams with powerful special attacks.
Set Details
Slowpoke's EV spread allows it to be as tanky as possible, enabling it to tank most physical and special attacks effectively. In addition, the HP EVs allow Slowpoke to reach 27 HP, which enables it to recover 9 HP when switching out instead of 8 HP. The remaining EVs are put into Slowpoke's Special Attack so it can retaliate with powerful moves after it tanks a hit, 2HKOing defensive Foongus and bulky Mienfoo with Psychic. The main EV spread and a Calm nature maximizes Special Defense, allowing Slowpoke to consistently avoid the OHKO from Life Orb Gastly's Shadow Ball and Snivy's Leaf Storm. Alternatively, the same EV spread can be run but with only 36 Special Attack and 76 Speed EVs, which allows Slowpoke to outspeed Foongus; however, the drop from 12 Special Attack to 11 worsens the damage rolls against 14 Special Defense Pokemon with Eviolite, meaning Slowpoke can't 2HKO Foongus with Psychic from full health anymore. If Calm Mind is run, a physically defensive EV spread of 116 HP / 236 Def / 116 SpA / 36 SpD should be used, turning Slowpoke into a more physically defensive tank that almost completely shuts down Mudbray, while also better checking Timburr without Bulk Up. Eviolite is very important to Slowpoke, as it helps Slowpoke tank moves more efficiently. Regenerator is very beneficial, as it allows Slowpoke to recover health while switching out, which it does often due to its defensive role.
Usage Tips
Slowpoke should be switched into Pokemon it can handle, tanking their hits and KOing them back. Slowpoke can also be sent out to force switches, although it should generally immediately switch out afterwards. Slowpoke also shouldn't be switched in and out randomly to just get its HP restored from Regenerator, as its checks are very common in the metagame, and if it switches in carelessly, it might take a super effective move such as Knock Off. Knock Off in general should be avoided, as it deals super effective damage and removes Slowpoke's important Eviolite, which hinders its bulk. Slowpoke can also spread paralysis once it switches in, potentially crippling fast offensive Pokemon. When Slowpoke reaches a low amount of HP, it should switch out to gain more HP and then switch into a Pokemon it can use Slack Off against so it can recover its HP fully. Slowpoke should avoid some mixed or special attackers, as its Special Defense is lacking compared to its Defense, meaning it might get KOed by powerful special attacks; it should still be able to switch into resisted special attacks, but should be wary in general. If Slowpoke is running Calm Mind, it should be kept healthy until late-game when most of its checks are defeated and it can set up on passive Pokemon or Pokemon whose attacks it resists and then clean the rest of the opposing team. Slowpoke can also consistently check hail teams, as it can take care of Slush Rush sweepers such as Alolan Sandshrew and hail setters such as Snover with Fire Blast.
Team Options
Grass-types make good teammates, as they can wall incoming Grass- and Electric-type attacks and provide good type synergy with Slowpoke, as Slowpoke can take care of the Fire- and Ice-type Pokemon Grass-types don't appreciate such as Ponyta and Alolan Sandshrew. Foongus and Ferroseed make great partners, and the latter can also set entry hazards to help Slowpoke take care of opposing Pokemon more easily. Slowpoke hates Knock Off, so Pokemon that don't mind Knock Off such as Sticky Hold users like Trubbish are great. Slowpoke can also wall Psychic-types for Trubbish, which in return can take of most Grass-types that don't have a secondary Poison typing. Pokemon that can check Grass-, Electric-, and Dark-type Pokemon are favorable. Pawniard deserves a mention here because it provides good type synergy with Slowpokeand appreciates Slowpoke's ability to spread paralysis. Vullaby also deserves a mention, as it can wall most Dark-types such as Scraggy and take care of Grass-types such as Foongus; it also provides nifty type synergy with Slowpoke, as the two form a nice core that can take on nearly everything except Electric-types. Fighting-type Pokemon such as Mienfoo can also be good teammates, as they can take care of Dark-types for Slowpoke, while Slowpoke can wall most Psychic-types and other checks. Mienfoo also forms a solid Regenerator core with Slowpoke and is a decent Knock Off absorber, especially if it runs Acrobatics.