Your starter, Kurotorofu, Moostar and Soliche are my recommendation. Pick 3 out of these 4.
The starter final form has the best stats in the game available to the player, cannot be affected by Abnormal Status, has a move that blocks damage and heals and dish out high damage while tanking them.
Kurotorofu
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It's a tank that can put multiple DoT debuffs and then just heal and stall out the enemy.
It's weak to enemies that cannot be DoT debuffed, so those that have the same ability as your starter.
Moostar:
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A tank that can increase it's defense and evasion a lot, it's special skill takes 50% of the enemies max hp if they miss, which will happen when you increase your evasion and any hits that do land can be tanked by it's high defense that you can boost further. It can potentially sweep all 3 enemies if it gets enough buffs off, especially since trainers often start with their weaker mons that gives you time to setup before their stronger mons come out.
It's weak to DoT because it cannot heal.
Last recommendation is Soliche:
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It's a Glass cannon that immediately applies Burn on the enemy (Burn does DoT and reduce enemy defense 25%), so it's a great mon to start off the battle, if you get a bad matchup you can switch to a better matchup while the enemy stays burned and then burn another target later when Soliche comes in again.
There might be more useful mons, but these 4 stands out for me.