Trainer cards are useful for enhancing one's tactics in the Pokemon TCG in a variety of ways, such as recovering precious pokemon or energy cards from the discard pile, helping a trainer evolve their pocket monsters, and much more.
There are many different types of Trainer cards, and one group stands out as particularly interesting because they can grant one's pokemon new moves to use in battle. Aptly named after their Pokemon video game counterparts, the TM Trainer cards can help give one an edge in battle that the opponent may not expect. Out of all such cards released in North America, a few stand out as being more useful than their brethren for how much they can hinder a foe's pokemon and tactics.
10 Fire Cube 01
A lot of the new moves that TM cards can grant are capable of inflicting a status condition to a foe. Singe, given by Fire Cube 01 from the Aquapolis set (as are all the "Cube" TM cards), can make the opposing pokemon become burned, like the effect from the attacks of some Fire pokemon.
In addition to making the afflicted immediately lose 20 HP, it will also cause them to lose 10 more each turn until that pokemon is switched out or healed in some way.
9 Technical Machine TS-1
Here's a TM card that's a bit newer than the Cube ones, though still possesses the same aesthetics. Technical Machine TS-1 from the Legends Awakened expansion can help a trainer evolve their benched pokemon quicker than normal thanks to the move Evoluter, which lets the active pokemon help their allies become stronger.
While a useful trait, it can be argued that using a regular Trainer card for this function is more optimal, as using Evoluter will prevent one's active pokemon from unleashing damaging attacks during their turn.
8 Grass Cube 01
Simultaneous status conditions are always a pain to deal with, and while there are quite a few pokemon (mostly Grass-types) that have moves that can pull of this two-pronged attack naturally, Grass Cube 01 is a way for trainers to teach this useful ability to any pokemon they desire.
Making a foe fall asleep while also causing them to become poisoned will prevent them from fighting back while also causing them to take 10 HP of damage every turn for an efficient way to lock down and hurt the opposing active pokemon with a single move.
7 Lightning Cube 01
This shocking little box of electric bolts is the Cube TM card that can potentially pack the most punch, though, delivering the optimal amount of damage will require some luck and the sacrifice of all Lightning energy attached to the pokemon using the mighty Discharge attack that Lightning Cube 01 grants.
Discharge is an attack that is better off used as a surprise finale or as an unexpected damage-dealing move from a Lighting-type pocket monster that possesses little or no way to hurt the opponent's active pokemon, for draining all the energy of a trainer's own active ally can leave one at a disadvantage.
6 Team Galactic's Invention G-107 Technical Machine G
While the move granted by the cumbersomely named Team Galactic's Invention G-107 Technical Machine G is quite situational, it can allow a trainer to turn the tide in battle. This TM Trainer card could be found in the Rising Rivals set, though, since it was released a while ago, collectors will likely have to look for this one online.
The move it teaches, Damage Porter, will let the equipped pokemon deal greater damage depending on how much HP they are missing, so would be ideal to reveal on a badly injured active ally as a last-stand kind of attack that can potentially knock out the rival's active pokemon in a sudden power-move.
5 Miracle Sphere β
On average, the TM Trainer cards from the Skyridge set (the "Sphere" ones with Greek letters) are objectively better since they deal damage and possess multiple beneficial secondary effects. To activate these bonus effects, however, trainers will need to make sure that the right kinds of energy are attached.
Miracle Sphere β grants the move Freezing Force, which will always deal 30 damage, though, if used while a Fire energy is attached will deal another 10 damage on top. Furthermore, also having a Psychic energy attached will grant an additional effect that causes the foe to remove an energy card from their active pokemon. Keep in mind that this is a single-turn deal, as Miracle Sphere β gets automatically discarded at the end of the turn it is played.
4 Miracle Sphere γ
Miracle Sphere γ acts similarly to Miracle Sphere β in that it deals a base of 30 damage while also being capable of an additional 10 plus a few other effects, though only on the turn it is played.
Lightning energy is the only required specified resource, however, the bonus 10 damage comes in when the equipped pokemon has a Grass energy attached. These 2 energy types together also cause the user of Thunder Force to inflict status conditions that both cause the target to fall asleep and become poisoned. Having a Water energy in the mix further allows 10 damage to be placed on each of the adversary's benched pokemon.
3 Miracle Sphere α
Many consider this to be the best out of the Miracle Sphere TM cards as in addition to dealing the same amount of damage as its brethren, Miracle Sphere α can let the equipped pokemon confuse foes as well as heal 30 HP worth of damage.
Just be sure to use this on a pokemon that has at least 1 Fire Energy, 1 Lightning energy, and 1 Fighting energy attached for optimal implementation on the turn that one wants to use the Fire Force move.
2 Technical Machine TS-2
Acting as a parallel to Technical Machine TS-1, which is also from the Legends Awakened set, Technical Machine TS-2 grants the equipped pokemon a move that devolves the foe's active pocket monster. When used, Devoluter will force the enemy's highest evolution stage to be returned to their owner's hand, which can significantly weaken them.
Though, since the opponent can just play that same evolution stage card on their next turn, it is advised to knock out their lesser form on the same turn or cause the opposing trainer to discard their hand.
1 Ancient Technical Machine [Rock]
Despite there being 3 "Ancient Technical Machine" Trainer cards in the Hidden Legends expansion, the best out of them is undeniably Ancient Technical Machine [Rock]. With just a single Colorless energy, a player's pokemon can use this TM's move to devolve all of an adversary's pokemon that are on the field simultaneously.
This can severely hinder them during the turn Stone Generator is used in a variety of different ways, however, like with Technical Machine TS-2, this tactic becomes exceptionally more devastating if paired with something that forces the adversary to discard their hand. Therefore, in one fell swoop, a trainer with Ancient Technical Machine [Rock] can send all of their foe's most powerful pokemon to the discard pile.