Can I use Heavy Ball or Level Ball to search for a Pokemon V-UNION card?
No you can't. Even if a Pokemon V-UNION has a Retreat Cost of 3 or more when it's fully assembled, you still can't search for any of the parts with Heavy Ball. And even though some of the parts don't have any HP listed, you still can't search for them with Level Ball.
Source: TPCi Rules Team (2021-09-30)
Can I use Heavy Ball to search for Wimpod that has the "Wimp Out" Ability on my first turn?
Yes, you can. Abilities only work when in play (unless the card says otherwise), so Wimp Out is not active while Wimpod is still in the deck.
Source: TPCi Rules Team (2017-09-14)
Can I use Heavy Ball to search for Chesnaught BREAK since it has the retreat cost of Chesnaught?
No. While not in play, the card has no Retreat Cost.
Source: BREAKthrough FAQ (2015-11-19), TPCi Rules Team (2015-11-19)
Can I use Heavy Ball to look for a LEGEND Pokemon half?
No, you cannot. The Retreat Cost is only printed on one half of the LEGEND Pokemon. If it is printed on both cards, then it is a common attribute for both pieces; but since it is printed on only one half it only applies to the LEGEND Pokemon when both pieces are in play.
Source: TPCi Rules Team (2012-04-05)
If Skyarrow Bridge is in play, can I still use Heavy Ball to search for a Basic Pokemon with a Retreat Cost of 3?
Yes, you can. The Retreat Cost reduction only applies to Basic Pokemon in play, and cards in your deck are not in play.
Source: Next Destinies FAQ (2012-02-09), TPCi Rules Team (2012-02-09)