Just to clarify, how do other lands count? Pendulums? Other: weapons?
I am assuming all count towards your off-element cards with the exception of same element pendulums correct?
I'm not too sure of the stance on Other cards (Dagger, Shortsword, Hammer, Shortbow), but I can give a ruling on Pendulums.
Example: Let's say that my main element is

and I wanted to play a Fractal Phoenix deck. If I included Fire Pendulums, then they would be treated as off-element cards (since their base element is

), regardless of what my mark is.