If Pokemon League Headquarters is in play and I have Lunatone with the "New Moon" Ability and also Solrock in play, do my Basic Pokemon have an extra {C} cost to their Attacks?
No, but your opponent's Pokemon do.
Source: Obsidian Flames FAQ; TPCi Rules Team (2023-08-10)
What happens if I play Worker and cannot draw any cards? Do I still get to discard a Stadium or not?
Yes, they are two separate sentences so you do as much of it as you can.
Source: TPCi Rules Team (2023-07-13)
Say Gapejaw Bog stadium and Ting-Lu ex with "Cursed Land" Ability are both in play. If I put Lumineon V onto the Bench, can I use its "Luminous Sign" Ability or will it be blocked because it has damage counters on it?
Since Luminous Sign and Gapejaw Bog are simultaneous effects, it is up to the player to choose the order in which they will be applied.
Source: TPCi Rules Team (2023-07-13)
My opponent has Malamar with the "Contrary" Ability in the Active Spot. On my turn, I attach Blunder Policy to my Fuecoco and use its "Spacing Out" attack and I flip heads. The coin result will be treated as tails, but since the physical coin flipped heads do I get to draw 3 cards with the effect of Blunder Policy?
There is no distinction between the actual result of the coin flip vs. what the outcome is treated as. Regardless of what the physical coin shows the flip was tails, so you would get to draw 3 cards from the effect of Blunder Policy.
Source: TPCi Rules Team (2023-06-22)
Can you use Lost Vacuum to put a card into the Lost Zone if there is no Stadiums or Tools in play?
No, you cannot. Putting a card into the Lost Zone is a cost not the effect, and you cannot play Trainer cards for no effect.
Source: TPCi Rules Team (2023-06-01)
If I have a Honchkrow V with "Boss Pockets" Ability and 190 damage on it and three Emergency Jelly tool cards are attached, do all of the tool cards trigger at the same time or do they trigger sequentially?
They trigger in sequence, so the first Emergency Jelly would remove 120 damage and get discarded, but the second & third Emergency Jelly would not trigger since there is now more than 30 HP remaining and no more damage would be healed.
Source: TPCi Rules Team (2023-04-13)
If I have 6 cards in my hand and use Mimikyu's "Impersonation" attack to discard Erika's Hospitality from my hand, can I use the effect of Erika's Hospitality?
Since you have 5 cards in your hand after discarding the Erika's Hospitality you can use its effect.
Source: TPCi Rules Team (2023-04-06)
If Temple of Sinnoh is in play, can I use Archeops' "Primal Turbo" Ability to attach a Rapid Strike Energy from my deck to a non-Rapid Strike Pokemon?
Yes, you can use Primal Turbo to attach Rapid Strike Energy to a non-Rapid Strike Pokemon. Normally Rapid Strike Energy would be discarded immediately, but Temple of Sinnoh removes all effects of Special Energy attached to Pokemon, so Rapid Strike Energy would not be discarded. But if Temple of Sinnoh's effect goes away, then Rapid Strike Energy would be discarded.
Source: TPCi Rules Team (2023-04-06)
Beginning with the Scarlet & Violet expansion, cards like Pokemon Catcher will now say "switch in 1 of your opponent's Benched Pokemon" to make it clear that the effect is on the Benched Pokemon. Likewise, the phrase "switch out" will be used if the effect is on the Active Pokemon. Older prints of these cards with different text that have the same game effect will therefore remain legal.
Source: Scarlet & Violet FAQ; TPCi Rules Team (2023-03-30)