Synonyms for Valuable:

adj.

expensive (adjective)
costly.
good (adjective)
worthwhile.
important (adjective)
fundamental, vital, major, meaningful, serious, significant, key, crucial, central.
instrumental (adjective)
essential, helpful, instrumental, useful, effectual, principle.
very important; priceless (adjective)
inestimable, expensive, costly, valued, high-priced, relevant, estimable, useful, helpful, important, dear, invaluable, scarce, of value, precious, Prized, treasured, worthy, worthwhile.

n.

high-powered, operative, practical, of great price, efficient, worthy, functional, beyond price, value, effective. helpful (noun)
worthy, relevant, expensive, estimable.
prized possession (noun)
antique.
valuable (noun)
precious, invaluable, of import, semiprecious, worthful, priceless, worth, important, valued, valued at, of value, rich, useful.

Other synonyms:

Prized, treasured, irreplaceable, functional. operative, meaningful, efficient, dear. gilt-edged, costly. effective. practical. costly
expensive.
priceless
priceless, inestimable.
Other relevant words:
irreplaceable, functional, worthy, worthful, rich, antique, invaluable, inestimable, worth, relevant, significant, high-priced, precious, costly, practical, expensive, scarce, worthwhile, treasured, efficient, of import, of value, valued, dear, priceless, important, estimable, of great price, beyond price, Prized, semiprecious, effective.

Usage examples for valuable

  1. The criminal law was the same for both; I have tried to find any difference, and this is all I have found: A woman's life was less valuable than a man's. – The Soul of a People by H. Fielding
  2. An orthodox creed is valuable if it influences action, but not otherwise. – Expositions of Holy Scripture: Romans Corinthians (To II Corinthians, Chap. V) by Alexander Maclaren