Can I use Salvatore to search my deck for a card that is not legal for play in the current tournament format? For example in a Standard format tournament, could I use Salvatore on a Raichu to search for Raichu BREAK?
No, a card has to be legal for play in the designated tournament format in order to be searched for by Salvatore.
Source: Temporal Forces FAQ; TPCi Rules Team (2024-03-21)

Relevant cards

Note: All applicable cards may not be listed below.
SV5_160
SV5_160