Any malts that start with cara- are crystal/caramel malts. Caravienna, Caramunich, Caraaroma, carared, cara-amber- all crystal malts.
Amber malt is a slightly darker base malt. The best sub would be biscuit malt or aromatic malt, but crystal malt would be acceptable but different.
Whats funny is that I have plenty of both biscuit and aromatic but used cara-amber instead. C'est la vie
Thanks Yooper.