Pokemon Ranger - Pokémon Rulings Compendium

If I use Medicham V's "Yoga Loop" attack to KO one of my opponent’s Pokemon, per the effect I get to take another new turn. If I then play Pokemon Ranger, can I use "Yoga Loop" again?: No, Pokemon Ranger won't bypass the repeat limitation of Yoga Loop because that is not an Attack Effect, it is a Game State Check. Yoga Loop is checking what the game state was in the past (did you use it last turn?), and Pokemon Ranger has no effect on that.

Source: TPCi Rules Team (2021-09-23)

If my opponent used Gardevoir EX's "Shining Wind" attack to gain "no Weakness" and I play Pokemon Ranger when it is my turn, does their Gardevoir EX have a Weakness again?: Yes. The ruling about effects on Weakness and Resistance not being ignored has to do with damage calculations [see "General Gameplay -> Weakness and Resistance" section for reference], not about whether a Pokemon HAS Weakness or Resistance. Pokemon Ranger removes attack effects, including this one; so yes, Gardevoir EX would have Weakness again after using Pokemon Ranger.

Source: TPCi Rules Team (2018-11-15)

If Darkrai attacks with "Abyssal Sleep", can Pokemon Ranger clear the effect of flipping 2 coins when Asleep?: Asleep, Poisoned, etc. are Special Conditions, regardless of how many coins you need to flip or how much damage the poison condition does. Therefore they are not altered by Pokemon Ranger.

Source: TPCi Rules Team (2016-11-10), TPCi Rules Team (2016-12-08)

If I used Mewtwo's "Barrier" attack last turn and this turn I play Pokemon Ranger, does that clear the effect so I can use "Barrier" again this turn?: No, Barrier does not "place an effect" to prevent its use on the next turn (unlike attacks such as "Volcanic Heat" which says "this Pokemon" cannot attack next turn). Instead, the attack does a Game State check to see if it was used last turn. Since there is no effect to clear, Pokemon Ranger won't allow you to use Barrier two turns in a row.

Source: TPCi Rules Team (2016-11-03), TPCi Rules Team (2016-12-01)

Can I play Pokemon Ranger if there are currently NO effects on either player or their Pokemon?: No, you cannot. You cannot play a Trainer card for no net effect.

Source: TPCi Rules Team (2016-09-08)

Pokemon Ranger says "remove all effects of attacks on each player and his or her Pokemon." Does that mean it gets to remove any Poison, Paralyze, etc. effects that were caused by an attack?: No, Pokemon Ranger does not remove any Special Conditions. It removes effects like "the Defending Pokemon cannot retreat", "the opponent cannot play any Item cards from his or her hand", and things like that.

Source: TPCi Rules Team (2016-08-11)