rotbtd
Rise of the Brave Tangled Dragons - also known as the Big Four, is a popular crossover consisting of Jack Frost (Rise of the Guardians, Dreamworks), Merida (Brave, Disney/Pixar), Rapunzel (Tangled, Disney), and Hiccup (How To Train Your Dragon, Dreamworks).
ROTBTD is my favorite crossover! I think Hiccup and Merida are so cute.