hello!! this is my first time building my own team (i usually play randoms on psd), so there are definitely huge flaws in this creation. any advice/constructive feedback is appreciated. :-)
i started with a tapu koko/alolan raichu core, since i recently played the main series sun/moon game for fun and became interested in the electric surge/surge surfer dynamic.
team:
Tapu Koko @ Heavy-Duty Boots
Ability: Electric Surge
EVs: 252 SpA / 4 SpD / 252 Spe
Timid Nature
IVs: 0 Atk
- Thunderbolt
- Dazzling Gleam
- Volt Switch
- Roost
i started with tapu koko because of its potential synergy with alolan raichu (due to electric surge making it a good electric terrain setter). tapu koko also has nice speed and potential to be a special attacker. i gave it thunderbolt and dazzling gleam for spA and stab, volt switch to chip damage when pivoting into alolan raichu or another mon, and roost to let it live longer.
Raichu-Alola (F) @ Choice Specs
Ability: Surge Surfer
EVs: 252 SpA / 4 SpD / 252 Spe
Modest Nature
IVs: 0 Atk
- Psychic
- Rising Voltage
- Volt Switch
- Surf
^ as said above, i picked alolan raichu for its synergy with tapu koko. surge surfer doubles alolan raichu's speed in electric terrain, so it can potentially outspeed and be a special sweeper. i gave it rising voltage because of its immense power in electric terrain, psychic for stab, volt switch to pivot into other mons if i'm facing danger, and surf (idk if this was a good choice, i picked it on the chance that i have the opportunity to finish off a dangerous opposing ground type, but i may be wrong here). i gave alolan raichu choice specs to boost spA even further.
Toxapex (F) @ Rocky Helmet
Ability: Regenerator
EVs: 252 HP / 252 Def / 4 SpD
Bold Nature
IVs: 0 Atk
- Toxic Spikes
- Scald
- Recover
- Haze
i picked toxapex next to deal with ground types, especially since it has good defense, allowing me to switch into it from the core pokemon i picked. i also gave it toxic spikes to set up hazards, recover to last longer as defense and stall poison, and haze to reset the opponent's stats if they're bulking up. i gave it the regenerator ability to keep it alive as well.
Rotom-Heat @ Heavy-Duty Boots
Ability: Levitate
EVs: 120 HP / 136 SpA / 252 Spe
Modest Nature
- Overheat
- Sucker Punch
- Defog
- Will-O-Wisp
i chose rotom-heat because of its levitate ability (useful against the ground types that are bad for my core), and it can deal with psychic enemies of toxapex with sucker punch while also resisting electric. i picked defog to get rid of hazards and will-o-wisp because burn is gr8. i also picked overheat because it's a powerful stab move.
Ferrothorn (F) @ Leftovers
Ability: Iron Barbs
EVs: 252 HP / 24 Def / 232 SpD
Sassy Nature
IVs: 0 Spe
- Stealth Rock
- Leech Seed
- Gyro Ball
- Power Whip
i feel that ferrothorn may be redundant, but i picked it to deal with water types threatening rotom-heat. i also felt that i needed more defensive pokemon, and ferrothorn is very resilient. i thought that it would be great for setting up stealth rock, and i gave it leech seed and leftovers to stay alive. i gave it gyro ball because it's super slow, power whip because it is a powerful move, and iron barbs to chip away at hp.
Swampert (F) @ Leftovers
Ability: Torrent
EVs: 176 HP / 252 Atk / 80 Def
Adamant Nature
- Flip Turn
- Waterfall
- Earthquake
- Stone Edge
i felt that i needed another tanky offensive pokemon, so i picked swampert to be an attacker because it has good typing and seems to deal with a lot of my other weaknesses. i picked waterfall, earthquake, and stone edge because they are powerful attack moves, and i added flip turn because it seemed useful (after playing a couple games, however, it didn't really seem that useful after all, so i'd probably like to replace it).
i started with a tapu koko/alolan raichu core, since i recently played the main series sun/moon game for fun and became interested in the electric surge/surge surfer dynamic.
team:
Tapu Koko @ Heavy-Duty Boots
Ability: Electric Surge
EVs: 252 SpA / 4 SpD / 252 Spe
Timid Nature
IVs: 0 Atk
- Thunderbolt
- Dazzling Gleam
- Volt Switch
- Roost
i started with tapu koko because of its potential synergy with alolan raichu (due to electric surge making it a good electric terrain setter). tapu koko also has nice speed and potential to be a special attacker. i gave it thunderbolt and dazzling gleam for spA and stab, volt switch to chip damage when pivoting into alolan raichu or another mon, and roost to let it live longer.
Raichu-Alola (F) @ Choice Specs
Ability: Surge Surfer
EVs: 252 SpA / 4 SpD / 252 Spe
Modest Nature
IVs: 0 Atk
- Psychic
- Rising Voltage
- Volt Switch
- Surf
^ as said above, i picked alolan raichu for its synergy with tapu koko. surge surfer doubles alolan raichu's speed in electric terrain, so it can potentially outspeed and be a special sweeper. i gave it rising voltage because of its immense power in electric terrain, psychic for stab, volt switch to pivot into other mons if i'm facing danger, and surf (idk if this was a good choice, i picked it on the chance that i have the opportunity to finish off a dangerous opposing ground type, but i may be wrong here). i gave alolan raichu choice specs to boost spA even further.
Toxapex (F) @ Rocky Helmet
Ability: Regenerator
EVs: 252 HP / 252 Def / 4 SpD
Bold Nature
IVs: 0 Atk
- Toxic Spikes
- Scald
- Recover
- Haze
i picked toxapex next to deal with ground types, especially since it has good defense, allowing me to switch into it from the core pokemon i picked. i also gave it toxic spikes to set up hazards, recover to last longer as defense and stall poison, and haze to reset the opponent's stats if they're bulking up. i gave it the regenerator ability to keep it alive as well.
Rotom-Heat @ Heavy-Duty Boots
Ability: Levitate
EVs: 120 HP / 136 SpA / 252 Spe
Modest Nature
- Overheat
- Sucker Punch
- Defog
- Will-O-Wisp
i chose rotom-heat because of its levitate ability (useful against the ground types that are bad for my core), and it can deal with psychic enemies of toxapex with sucker punch while also resisting electric. i picked defog to get rid of hazards and will-o-wisp because burn is gr8. i also picked overheat because it's a powerful stab move.
Ferrothorn (F) @ Leftovers
Ability: Iron Barbs
EVs: 252 HP / 24 Def / 232 SpD
Sassy Nature
IVs: 0 Spe
- Stealth Rock
- Leech Seed
- Gyro Ball
- Power Whip
i feel that ferrothorn may be redundant, but i picked it to deal with water types threatening rotom-heat. i also felt that i needed more defensive pokemon, and ferrothorn is very resilient. i thought that it would be great for setting up stealth rock, and i gave it leech seed and leftovers to stay alive. i gave it gyro ball because it's super slow, power whip because it is a powerful move, and iron barbs to chip away at hp.
Swampert (F) @ Leftovers
Ability: Torrent
EVs: 176 HP / 252 Atk / 80 Def
Adamant Nature
- Flip Turn
- Waterfall
- Earthquake
- Stone Edge
i felt that i needed another tanky offensive pokemon, so i picked swampert to be an attacker because it has good typing and seems to deal with a lot of my other weaknesses. i picked waterfall, earthquake, and stone edge because they are powerful attack moves, and i added flip turn because it seemed useful (after playing a couple games, however, it didn't really seem that useful after all, so i'd probably like to replace it).
that can set up in front most of your mons and easily sweep. Toxic Landorus 
could also be annoying as well as things like Heatran 
or Choice specs Dragapult 
that won’t have too much trouble coming and taking kills. I also think that strong grass hitters like Rillaboom 
or Kartana 
can be hard to deal with depending on there set as Rotom-heat doesn’t have a good recovery move.
Your koko set is good, however, I think that U-turn would be a best move for pivoting than Volt Switch mainly because koko will attract a lot of grounds types and you want to be able to pivot on them.
I don’t know if Specs Raichu is the most efficient way to play it. It’s really threatening when electric terrain is up, but it requires to anticipate well what your opponent will do. I can suggest you to give a try to a nasty plot variant (set is just below). Also, I feel that Psyshock might be better than Psychic do hit special defensive wall like Blissey.
Your toxapex set is fine. Knock Off could be an option but I think that Toxic Spikes are better to pressure a lot of mons that comes on Raichu. (However, Toxapex doesn’t help much dealing with ground types as even if it has an incredible bulk, most Earthquakes still do too much damage).
Probably the biggest change in the team, I think you should change him for something like 
. Indeed, Mandibuzz will help dealing with most ground types: Garchomp, Excadrill, some Landorus sets. It is also really good against Dragapult and can help a lot against Rillaboom and Kartana. Here is the set I would suggest for Mandibuzz:
Ferrothorn could be a nice hazard setter as hazards + Alolan Raichu work really well. Thus, I think you rather have Spikes on Ferro (and you could move Rocks to Swampert but I’ll talk about him just after). I also think you should use Knock Off to annoy some defoggers. Here is the set I would suggest:
I think a more Special defensive Swampert will work better here. It will help dealing with hard special hitter or mons like Heatran way more efficiently. Thus, I suggest giving him Rocks and Toxic instead of Waterfall and Stone Edge so that you can set up hazards in combination with Ferro and pivot into Koko or Raichu. Toxic can annoy a lot of defoggers or mons that easily come on Swampert. Playing an ice move instead of Toxic is also an option. (Min speed is for having a slow pivot) Here is the Swampert set: