Taiyaki is a kind of waffle that has red bean stuffed inside. It has the shape of sea bass, hence the name. (Tai = sea bass)
Dorayaki is a pancake sandwich that has red bean inside. It's Doraemon's favorite snack.
Actually almost all Japanese traditional snack is very sweet because it's based on azuki bean (red bean). I think if you interest in wagashi may be you could read this in Wikipedia
Wagashi - Wikipedia, the free encyclopedia