What are other kinds of fistula?

Innumerable. There are dozens of different kinds. A fistula is basically an abnormal connection between parts of the body. You can have fistulas between the arteries & veins, small bowel & colon, intestine & bladder, bowel & vagina, lungs & bile ducts, stomach & lungs, esophagus & trachea.... I think you get the idea.
Anal fistulas. This can be a follow up complication of perirectal abscesses.