What is the complete subject in the sentence Mythical creatures such as mermaids and mermen are often found in art and literature?

The complete subject in the sentence is "Mythical creatures such as mermaids and mermen." This phrase identifies the main topic of the sentence, which is about the various mythical beings that are commonly depicted in art and literature. The additional phrase "such as mermaids and mermen" provides specific examples of the mythical creatures being referenced.