Battle Lock : set the battle position of a monster for a number of turns (if no turn is specified then its permanent as long as this effect is active)
Since you don't need to waste slots on evasion you can just bring it with game-winning equipment like Blackblade Reforged or spells like Might of Oaks
Phantom Knights, 2 Destiny HERO Phantom Knights) 21 Dragonmaid (18 Dragonmaid, 3 Destiny HERO Dragonmaid) 20 Floowandereeze (15 Floowandereeze, 5 Dogmatika Floowandereeze) 19 @Ignister 16 Zefra 15 Orcust (7 Destiny HERO Orcust, 5 Orcust, 1 Grass Destiny HERO Orcust, 1 Grass Mekk-Knight Orcust, 1 Mekk-Knight Orcust) 14 Tri-Brigade Lyrilusc 13 Code Talker (1 Code Talker, 1 Invoked Code Talker) 13 Invoked (8 Destiny HERO Invoked, 2 Dogmatika Invoked, 1 Destiny HERO Artifact Invoked, 1 Destiny HERO Dogmatika Invoked, 1 1 Destiny HERO Nemeses Invoked) 13 Magician 12 Endymion 12 Thunder Dragon (5 Chaos Thunder Dragon, 3 Destiny HERO Thunder Dragon, 2 Thunder Dragon, 2 Destiny HERO Chaos Thunder Dragon) 9 Adamancipator (6 Adamancipator, 1 Destiny HERO Adamancipator, 1 Grass Destiny HERO Adamancipator, 1 Grass P.U.N.K

If you're more concerned with brute strength than aesthetics, though, we have got a Temtem tier list detailing the most powerful creatures you can pick up on your quest to become the strongest trainer in the land