Besides from Dugway Thundereggs, Utah is known for several agatized fossils including woods and dinosaur bones. The Yellow Cat area produced a number of  agatized woods showing yellow, red, and gray banded agates while few dinosaur bones from Morrison Formation contained the bright pink, white, red and yellow agates filling in the voids. The best agates are usually in large dinosaur bone specimens and quite expensive to obtain. It must be cautioned that there are some regulations governing the collecting of dinosaur bones and even I do not know if they can be collected at all!