Cessation Crystal is a widely played anti-Power/Body card. It's frequently found in decks with strong, non-ex Basics or Stage 1s that don't require much setup.
Stantler is a notable abuser of Cessation Crystal, as it has high HP for a Basic, no Powers/Bodies, and an attack that discards common answers to Cessation Crystal.
Cessation Crystal can be used even in decks that include Pokémon with Powers/Bodies, such as Electrode ex. If your Active Pokémon has a Crystal equipped, you can retreat it in order to use a Power.
Cessation Crystal can shut off inhibitory Poké-Bodies, such as Team Magma's Groudon's Power Saver or Sceptile ex δ's Extra Liquid. (This is a good thing if you have Groudon with a Crystal on it, or a bad thing if you have a Crystal-equipped Pokémon and your opponent has a Sceptile ex δ.)
Cessation Crystal can be countered by Windstorm, or any card that forces the opponent to switch (Warp Point, Pow! Hand Extension, Cyclone Energy, Pokémon Reversal). Sceptile ex δ punishes Cessation Crystal by attacking for only {P}{C} against Crystal-equipped Pokémon.
Extra Liquid stops Powers from Pokémon-ex. The main targets are Electrode ex and Gardevoir ex δ; secondary targets are Blastoise ex, Swampert ex, Meganium ex, and all ex Eeveelutions.
The other half of Extra Liquid is making attacks from ex's cost more. This can buy some time against aggressive decks that want to start attacking with a Stage 1 ex as quickly as possible.
Power Revenge is a strong late-game attack, even factoring in the cost increase from Sceptile's own Extra Liquid. It maxes out at 110 damage for 3 Energy. If the Defending Pokémon has a Cessation Crystal equipped, Power Revenge's cost returns to {P}{C}.
Even though Sceptile ex δ is a Stage 2, it's not too hard to fit into decks that already play Rare Candy. A 1-0-1 line will do just fine.
The main counters to Sceptile ex δ are Mew δ and Roselia. Mew δ can copy Power Revenge for {P}{C} and get double damage from Weakness, 1HKOing Sceptile if they've taken even a single Prize. However, this is only good for beating Sceptile if your opponent is eventually going to put Sceptile Active and attack with it; if they're just chilling with Sceptile on their Bench to shut off your ex Powers, you'd need to find a way to force it out before you can KO it with Mew. Roselia is a softer counter: it can force Sceptile out and wear it down with Poison, demanding a switch/retreat from the opponent while also making it easier to KO later.
This is a card that you typically only find in its own deck, but what a powerful card it is! It has both offensive and defensive uses: offensively, it can shut off your opponent's Pidgeot and other CA engines. Defensively, it can shut off your opponent's Solrock so your own Pidgeot can Quick Search, or remove Safeguard so it can KO an otherwise immune Pokémon.
One flaw of Imprison is that you cannot stop an Evolved Pokémon from using its Power/Body by Imprisoning the Basic form, because Imprison markers are removed upon (d)evolution. Electrode ex is one such Pokémon that slips through Gardevoir's net, as it can evolve from Voltorb and immediately blow up before Gardevoir can Imprison it.
The main counter to Gardevoir ex δ is Sceptile ex δ. Amusingly, they hit each other for Weakness, though Sceptile has the upper hand as it attacks for 3 Energy instead of 4 (after Extra Liquid). Tropius δ or Surprise! Time Machine can remove Imprison markers. For revenge killing Gardevoir, Ditto (the Psychic-type one with Copy) will do — copying Flame Ball lets you move Energy off Ditto, minimizing the loss if Ditto gets revenge killed in return.
Luna Shade shuts off Pidgeot's Quick Search, Delcatty's Energy Draw, and Aipom's Snappy Move.
Sol Shade shuts off Team Magma's Camerupt's Overheat, Magcargo's Smooth Over, Milotic δ's Sharing, and Blaziken's Firestarter. These are not too common, so other Lunatones may be used instead of the Sol Shade one. Note that it does not shut off Gardevoir ex δ's Imprison, as it specifies non-Pokémon-ex.
Giant Stump is an effective counter to Lunatone + Solrock, as it forces them to either lose the lock entirely, or work with only 2 other Pokémon.
Rear Sensor shuts off Jirachi's Wishing Star.
Note that it only shuts off Active Basic Pokémon's Poké-Powers, so things like Benched Aipom or Chimecho δ are unaffected.
Dual Aura shuts off several Evolved Pokémon's Poké-Bodies:
Houndoom's Lonesome
Dugtrio's Sand Veil
Stages of Evolution and Safeguard
Note that it does not shut off Sceptile ex δ's Extra Liquid, as it specifies non-Pokémon-ex. Also, like with Lunatone + Solrock, Latias δ needs a partner (Latios ex δ) in order to turn on Dual Aura.
Shield Beam prevents your opponent from using Poké-Powers.
If your opponent has Pidgeot in play, that's enough to count for Star Light's cost reduction.
Shield Beam can pre-emptively stop Electrode ex, so sometimes you will see it in Gardevoir decks to cover the one prominent Pokémon that Imprison misses.
Since Jirachi ex has to attack in order to maintain the lock, disabling Special Conditions (Paralysis, Sleep, Confusion) can buy you a turn of respite. Another counter is to put an ex-immune Pokémon (e.g. Latios ex δ, Celebi ex) up against it.
This mainly shuts off Pidgeot, but it also hits Dragtrode, Gardevoir δ, and Delcatty.
Since it's a Stadium, it's vulnerable to Windstorm or counter Stadiums. Trainer lock decks like Manectric ex or Dragonite ex δ can protect it from removal.
Umbreon ex can force in a Pokémon with Darker Ring, keeping it trapped and unable to use its Powers with Black Cry.
This shuts off the Poké-Bodies of four Basic Pokémon mentioned so far: Lunatone + Solrock, Girafarig, Latias δ.
Space Center was more common in the 2006 format. Some Delcatty builds in RS-PK still play it.
Delta Reserve stops Powers from non-δ Pokémon.
It's not common, as it's incredibly resource-intensive, being not only a Stage 2, but also requiring a Holon Energy card to do its thing. It also loses to Gardevoir ex δ's Imprison.