When I use the Supporter "Fisherman," can I put less than 4 Basic Energy cards from my discard pile into my hand?
If you have 4 or more Basic Energy cards in the discard pile you must put exactly 4 of them into your hand. But if there are less than 4 Basic Energy cards in the discard pile, you must take them all.
Source: HeartGold & SoulSilver FAQ (2010-02-11), PUI Rules Team (2010-02-11)
Can I play the Supporter "Copycat" when it's the only card in my hand?
Yes, you can. Shuffle your deck, then draw cards equal to the number of cards in your opponent's hand.
Source: HeartGold & SoulSilver FAQ (2010-02-11), PUI Rules Team (2010-02-11)
Can I use "Pokemon Collector" to choose Pokemon LEGEND cards as part of the 3 Basic Pokemon I search for in my deck?
No, because Pokemon Collector only lets you choose Basic Pokemon. Pokemon LEGEND are considered "Unevolved Pokemon" when in play, but they are not considered "Basic Pokemon".
Source: HeartGold & SoulSilver FAQ (2010-02-11), PUI Rules Team (2010-02-11)
Can I use the Supporter "Copycat" when my opponent has no cards in his or her hand?
Yes, you can. Shuffle your hand into your deck, but don't draw any cards.
Source: HeartGold & SoulSilver FAQ (2010-02-11), PUI Rules Team (2010-02-11)
Can I use cards that search for a Pokemon, like "Bebe's Search" or "Poke Ball" to get a Pokemon LEGEND card from my deck?
Any effect that lets you search your deck or discard pile or do something from your hand with "a Pokemon" will let you use that effect on one half of a Pokemon LEGEND set, but not both halves.
Source: HeartGold & SoulSilver FAQ (2010-02-11), PUI Rules Team (2010-02-11)
If I use Pokemon Communication to put a Pokemon into my deck, am I allowed to voluntarily fail and choose to take no Pokemon out of my deck?
The contents of your deck is not public knowledge so the deck search can fail, even if you've just put a Pokemon into the deck.
Source: PUI Rules Team (2010-02-04)
Can I use Rare Candy to evolve from Dome Fossil to one of the Kabutops from older expansions that evolve from Mysterious Fossil?
Since Kabutops can evolve from Kabuto of any expansion, you may use Rare Candy to evolve either Dome Fossil or Mysterious Fossil into any Kabutops, regardless of expansion.
Source: PUI Rules Team (2008-05-22)
I have never had this come up and I can't find anything saying you can't, but can you attach 2 Technical Machines to the same Pokémon at the same time?
There are no restrictions on TM's that say you cannot, so yes you can.
Source: PUI Rules Team (2006-01-26)
Could I play a trainer if it's obvious that it will have no effect (i.e. Life Herb on a Pokémon without any damage and with no Special Conditions on it)?
No, you cannot play a card if it is obvious that you cannot do what the card is supposed to do at that moment.
Source: PUI Rules Team (2005-09-22)