Z-Moves are already have a high skill ceiling and the potential to swing game momentum in your favor after one attack. But Z-Effect Moves are an entirely different ballgame with the same idea. The best way to give a good idea of what strengths come from each type is to give an example. There are a lot of crazy combinations to try; just remember that your plan will be exposed for one turn for the opponent to prepare for these once-per-game attacks.
Colorless
It’s your parting gift for the bench. Z-Call for Family not only will grab you two basic Pokémon that are ready to evolve next turn, but you will be able to attach one of any energy from your deck to them and then draw up to five cards. Pokémon like Ursaring will be ready to use their strong attacks next turn thanks to how fast a Double Colorless Energy attachment will be. Also, all five of the cards you draw will have shuffle armor next turn, so the opponent can’t undermine your new resources with N or Judge.
Grass
Drawup Power is already a strong attack. But with a Z-Crystal, you’ll be able to attach any and all of those energy cards to your Pokémon in any way you like, healing 30 for each attachment. This will also activate if you use Lure Poison, which can serve to entirely swing the game in your favor as the opponent panics to retreat.
Fire
Normally, Volcarona with a Z-Crystal will do the extra damage instead. But with Technical Machine-TS2 or Ancient Technical Machine – Rock, you’re doing a non-damaging attack that will activate the 40 damage burn that always results in tails. Add the fact that Volcarona’s Poke-Body adds another 10 for burn and that you’ve just De-evolved the Defending Pokémon, and you’re looking at an easy KO.
Water
This one you’ll most likely want to attach to the bench. If you don’t have the time due to damage, a Z-Jet Return will most likely get a KO. But if the situation presents itself, a Z-Guzzle will not only attach three Water to Pelipper and heal 30, but the Z-Crystal Effect will have Jet Return attack both the Defending and one Benched Pokémon next turn, which will grant you two KOs in most situations.
Psychic
Using Close Encounter will grant you three supporter and stadium cards in any combination. The Z-Effect will leave the opponent double-poisoned for as long as they stay in play. This means that evolving or moving to the bench will not get rid of this double poison. Grab a Lysandre, Virbank City Gym and something to draw cards to keep the pressure going while the target eventually gets knocked out.
Fighting
Z-Coil will grant Sandaconda a permanent 30 damage modifier and +10 defense afterward. The big secret comes from the fact that if your opponent ever has their active Pokémon leave the bench, they will always take 30 damage as long as Sandaconda is in play. Sandaconda will already be hard to knock out, and staying benched with a Coil counter will aid in all of your coin flipping effects, like Life Herb and Pokémon Catcher, to cause even more panic for the opponent.
Darkness
Z-Impersonate with a card like Professor’s Research will grant you a free attachment from the Discard Pile after discarding it from your hand for 7 new cards. The 70 damage spread is good by itself, but if you do Z-Impersonate as early as the second turn, the opponent most likely will not have a full bench, placing a lot of damage on the Defending Pokémon.
Metal
Go big or go home. Painful Sword is already a game-winning attack, but adding the Z-Crystal effect will make Aegislash always take 20 less damage from all attacks while never being able to be hit by your opponent’s Pokémon-EX while out. Adding insult to injury is Aegislash’s Poke-Body, preventing the opponent from sneaking in a weakness-prone attack to undermine your win condition. Allowing you to continue the painful sword pressure to win a game that might have already been won in some cases.
Lightning
Z-Charge will have Thundurus ready to deal a lot of damage… but it doesn’t have to be right then and there. As long as Thundurus stays on the board, the opponent will now have to take 20 damage on any Pokémon they attach energy to from their hand for the rest of the game. Keep Thundurus benched for as long as possible; if you think he’s going to get KOd, he’ll most likely have a Disaster Volt for 80 damage ready to end with.
Dragon
Already hurting the opponent’s set up with Time Aura, Dialga’s Z-Time Call will discard the top six cards in your opponent’s deck after you evolve one of your Pokémon and draw two. Creating a huge gap in resources and momentum as early as the second turn.
Fairy
Z-Geomancy will already accelerate energy for your Pokémon. But now Xerneas can freely retreat while having 20 more HP for the rest of the game. Keep this 120 HP tank alive on the bench for as long as possible as you use the added Z-Effect of discarding one random card from your opponent’s hand at the start of every turn they take.