What does Maki roll have?

Excuse me, could you please elaborate on what ingredients typically go into a Maki roll? I'm curious to know what makes up this popular Japanese sushi dish. Does it typically include seafood such as tuna or salmon? Are there any vegetables that are commonly used? Also, what type of rice is used, and is there a specific way it's seasoned? Lastly, do Maki rolls often come with a sauce or condiment for dipping? I'm quite interested in learning more about the composition of this sushi staple.