Looks like a good start! I like monotype, and I also have a Mono Psychic team, so let's get started! By looking at your team, it seems like you play doubles, because you have some Pokémon, like Meowstic and Farigiraf which are more Doubles Pokémon than Singles. Anyway, let's go through this team member by member.
Metagross:
Pretty good, but the EVs are kind of weird. I would go Adamant nature, and 252 HP, 252 Atk, 4 Def.
Meowstic:
Don't use Meowstic-F. Meowstic-M has Prankster, which makes all the difference. Don't use Sucker Punch either. Here is a set that would work better:
Meowstic (M) @ Light Clay
Ability: Prankster
Tera Type: Psychic
EVs: 252 HP / 108 Def / 148 SpD
Bold Nature
IVs: 0 Atk
- Light Screen
- Reflect
- Thunder Wave
- Psychic Noise
Also, if you're going to use screens, use a Pokémon who can use the screens to set up. Here are a few options:
All of these should go over Farigiraf, who isn't as needed.
Iron Crown @ Leftovers
Ability: Quark Drive
Tera Type: Steel
EVs: 252 HP / 252 Def / 4 Spe
Bold Nature
IVs: 20 Atk
- Calm Mind
- Agility
- Stored Power
- Tachyon Cutter
Iron Boulder @ Leftovers
Ability: Quark Drive
Tera Type: Rock
EVs: 4 HP / 252 Atk / 252 Spe
Jolly Nature
- Swords Dance
- Earthquake
- Mighty Cleave
- Zen Headbutt
Hatterene (F) @ Leftovers
Ability: Magic Bounce
Tera Type: Psychic
EVs: 252 HP / 252 Def / 4 Spe
Bold Nature
IVs: 0 Atk
- Agility
- Calm Mind
- Stored Power
- Dazzling Gleam/Draining Kiss
Any of these three would work well as a setup sweeper you could use under dual screens.
Gallade:
Choiced Gallade is good, but you have the wrong choice item. Gallade isn't bulky by anyone's standards, and is slow too. Use a Choice Scarf instead.
Slowbro-G:
Good, but Prankster Meowstic already has T-wave, so replace with Calm Mind for setup, or Yawn to force a switch. Also, 252 Hp, 252 Def and Relaxed nature if you use Calm Mind. If not, 252 HP, 72 Def, 184 Spd and Sassy nature. Also, you have recovery in Slack Off, so consider using Quick Claw instead for a higher chance of going first.
Rabsca:
It's ok, but Revival Blessing is kind of a gimmick, I've tried it, and it doesn't work that well. You could keep it, but I'd use Indeedee, for Terrain, Hoopa-U for Power, or a Latios set.
There you have it. I hope I helped, and good luck!