Psychic is a pretty tough type in this format. I managed to get a streak I'm happy with, but there were a lot of miserable failures to get there.
Gallade (M) @ Shell Bell
Ability: Justified
EVs: 4 HP / 252 Atk / 252 Spe
Jolly Nature
- Low Kick
- Drain Punch
- Zen Headbutt
- Aerial Ace
Espeon @ Life Orb
Ability: Magic Bounce
EVs: 4 HP / 252 SpA / 252 Spe
Timid Nature
IVs: 0 Atk
- Psyshock
- Shadow Ball
- Dazzling Gleam
- Grass Knot
Musharna @ Leftovers
Ability: Synchronize
EVs: 252 HP / 252 Def / 4 SpD
Bold Nature
IVs: 0 Atk
- Toxic
- Protect
- Moonlight
- Healing Wish
It would be a bit tough to explain how I decided on each Pokemon, move, and item without listing the exact trial-and-error process I went through. I didn't take notes on that, but this should be pretty close to what my team progression looked like:
Starmie/Rapidash-G/Indeedee
Rapidash-G/Gardevoir/Indeedee
Gallade/Gardevoir/Indeedee
Gallade/Gardevoir/Hatterene
Gallade/Espeon/Hatterene
Gallade/Espeon/Musharna
I think Gallade is the best lead sweeper in this format (Gardevoir and Espeon are both decent as well, but really lack the moves to benefit from Dynamax affects - there are a lot of overlapping terrain moves). My original Gallade moveset was Low Kick/Aerial Ace/Earthquake/Leaf Blade. Eventually I realized that putting up Psychic Terrain with Max Mindstorm was HUGELY advantageous for a psychic team, as that stops First Impression, Sucker Punch, and Shadow Sneak from wrecking your team. Those first two moves are a huge problem for this team if Psychic Terrain isn't up. It's also STAB, and has a higher neutral BP than any Fighting move in Dynamax.
But Gallade was still underperforming a little bit. I thought to replace Low Kick (32 PP) with Drain Punch (16 PP), but at this point even Low Kick was regularly running low on PP. So I got rid of Leaf Blade, and never really missed it. Drain Punch replaced the need for the healing from Grassy Terrain. Usually in Dynamax, I would try to use one Airstream, one Knuckle, and one Mindstorm. You won't always be able to do that, but if you do it pretty much puts you in a position to beat nearly anything when Dynamax runs out. And if you have two Knuckles up - or one Knuckle and a Defiant boost - Drain Punch is set to heal a ton of HP back. I think my best run with Gallade alone was about 18ish wins. I was also incredibly lucky with Zen Headbutt hits - I think I missed only once or twice in all my attempts. But I only used it when absolutely necessary. There are also a small number of Pokemon - Beartic comes to mind - where you can lead the battle with a straight Low Kick.
Espeon has two main purposes: Revenge Killing for Gallade, and Magic Bouncing. With a Timid nature, you can swap into Froslass's Will-o-Wisp and OHKO with Shadow Ball. You can swap into Yawn, Thunder Wave, and even Disable. At first I gave it Leftovers, but found it was missing OHKOs by a little bit. I also tried Expert Belt, but its coverage isn't amazing so it wasn't that useful. I tried out Life Orb and found that most battles starting with Espeon were simply 3 OHKOs in Dynamax (in this case the best defense was a strong offense). Plus, Life Orb recoil in Dynamax is halved (percentage-wise) due to the increase in HP. And if you use a Max Overgrowth, it negates about 2/3 of the Life Orb damage each turn. I also tried Choice Scarf+Modest, since one of its main roles was to revenge kill for Gallade, but again, it didn't do enough damage. So for the first time, I used Life Orb on a team and found it to work better than anything else.
The absolute best thing to happen to this team was finding Musharna. I kinda figured Indeedee would be necessary for Ghost immunity, but it ended up holding me back. Its Special Attack and Speed are a bit too low to swap into Ghost moves and OHKO back, and it got flattened by dark moves. I had better luck with Hatterene with Healing Wish, but I found its lack of a recovery move to be very troublesome. So I transferred over a Toxic Musharna and gave it a try. Once I found out all of the matchups that Gallade can't handle, it became a perfect swap Pokemon. At first I used Kasib Berry, because Shell Bell and Leftovers were taken by Gallade and Espeon, but eventually I decided on Life Orb for Espeon which freed up Leftovers for Musharna.
Healing Wish is very useful. Not a lot of stuff 2HKOs Musharna (but there are some strong Ghost and Dark moves that will, so be careful), so if your main sweeper is hurting and/or afflicted with status, you can swap in and use it. I also tried one with Heal Bell over Healing Wish, but found that status was pretty easy to bounce back with Espeon. And lastly, you can swap Musharna into Trick Room users. It won't outspeed all of them though, unless you use a hindering nature and 0 IVs. Note that if you outspeed in Trick Room, the AI usually uses Trick Room again to nullify its affects. Also, don't look away when using this Musharna, as tempting as it may be. You'll get taunted and use struggle at some point.
Gallade (M) @ Shell Bell
Ability: Justified
EVs: 4 HP / 252 Atk / 252 Spe
Jolly Nature
- Low Kick
- Drain Punch
- Zen Headbutt
- Aerial Ace
Espeon @ Life Orb
Ability: Magic Bounce
EVs: 4 HP / 252 SpA / 252 Spe
Timid Nature
IVs: 0 Atk
- Psyshock
- Shadow Ball
- Dazzling Gleam
- Grass Knot
Musharna @ Leftovers
Ability: Synchronize
EVs: 252 HP / 252 Def / 4 SpD
Bold Nature
IVs: 0 Atk
- Toxic
- Protect
- Moonlight
- Healing Wish
It would be a bit tough to explain how I decided on each Pokemon, move, and item without listing the exact trial-and-error process I went through. I didn't take notes on that, but this should be pretty close to what my team progression looked like:
Starmie/Rapidash-G/Indeedee
Rapidash-G/Gardevoir/Indeedee
Gallade/Gardevoir/Indeedee
Gallade/Gardevoir/Hatterene
Gallade/Espeon/Hatterene
Gallade/Espeon/Musharna
I think Gallade is the best lead sweeper in this format (Gardevoir and Espeon are both decent as well, but really lack the moves to benefit from Dynamax affects - there are a lot of overlapping terrain moves). My original Gallade moveset was Low Kick/Aerial Ace/Earthquake/Leaf Blade. Eventually I realized that putting up Psychic Terrain with Max Mindstorm was HUGELY advantageous for a psychic team, as that stops First Impression, Sucker Punch, and Shadow Sneak from wrecking your team. Those first two moves are a huge problem for this team if Psychic Terrain isn't up. It's also STAB, and has a higher neutral BP than any Fighting move in Dynamax.
But Gallade was still underperforming a little bit. I thought to replace Low Kick (32 PP) with Drain Punch (16 PP), but at this point even Low Kick was regularly running low on PP. So I got rid of Leaf Blade, and never really missed it. Drain Punch replaced the need for the healing from Grassy Terrain. Usually in Dynamax, I would try to use one Airstream, one Knuckle, and one Mindstorm. You won't always be able to do that, but if you do it pretty much puts you in a position to beat nearly anything when Dynamax runs out. And if you have two Knuckles up - or one Knuckle and a Defiant boost - Drain Punch is set to heal a ton of HP back. I think my best run with Gallade alone was about 18ish wins. I was also incredibly lucky with Zen Headbutt hits - I think I missed only once or twice in all my attempts. But I only used it when absolutely necessary. There are also a small number of Pokemon - Beartic comes to mind - where you can lead the battle with a straight Low Kick.
Espeon has two main purposes: Revenge Killing for Gallade, and Magic Bouncing. With a Timid nature, you can swap into Froslass's Will-o-Wisp and OHKO with Shadow Ball. You can swap into Yawn, Thunder Wave, and even Disable. At first I gave it Leftovers, but found it was missing OHKOs by a little bit. I also tried Expert Belt, but its coverage isn't amazing so it wasn't that useful. I tried out Life Orb and found that most battles starting with Espeon were simply 3 OHKOs in Dynamax (in this case the best defense was a strong offense). Plus, Life Orb recoil in Dynamax is halved (percentage-wise) due to the increase in HP. And if you use a Max Overgrowth, it negates about 2/3 of the Life Orb damage each turn. I also tried Choice Scarf+Modest, since one of its main roles was to revenge kill for Gallade, but again, it didn't do enough damage. So for the first time, I used Life Orb on a team and found it to work better than anything else.
The absolute best thing to happen to this team was finding Musharna. I kinda figured Indeedee would be necessary for Ghost immunity, but it ended up holding me back. Its Special Attack and Speed are a bit too low to swap into Ghost moves and OHKO back, and it got flattened by dark moves. I had better luck with Hatterene with Healing Wish, but I found its lack of a recovery move to be very troublesome. So I transferred over a Toxic Musharna and gave it a try. Once I found out all of the matchups that Gallade can't handle, it became a perfect swap Pokemon. At first I used Kasib Berry, because Shell Bell and Leftovers were taken by Gallade and Espeon, but eventually I decided on Life Orb for Espeon which freed up Leftovers for Musharna.
Healing Wish is very useful. Not a lot of stuff 2HKOs Musharna (but there are some strong Ghost and Dark moves that will, so be careful), so if your main sweeper is hurting and/or afflicted with status, you can swap in and use it. I also tried one with Heal Bell over Healing Wish, but found that status was pretty easy to bounce back with Espeon. And lastly, you can swap Musharna into Trick Room users. It won't outspeed all of them though, unless you use a hindering nature and 0 IVs. Note that if you outspeed in Trick Room, the AI usually uses Trick Room again to nullify its affects. Also, don't look away when using this Musharna, as tempting as it may be. You'll get taunted and use struggle at some point.