Rodrigo, a 22-time Spain international, is the most high profile of all of those mentioned and is available.
Valencia are suffering major financial problems, meaning most of their squad is available for the right price.
Rodrigo is a proven striker who would add experience and quality to the Leeds side following their return to the Premier League.
In 220 appearances for Valencia, Brazil-born Rodrigo has scored 59 goals and delivered 44 assists.
He is no stranger to the north of England, having spent some time at Bolton in his youth.