Personally I think that (cartesian-product) and (partial-orders) are superfluous.
I am not sure about partial-orders. Would posets deserve separate tag? Would equivalence relations deserve separate tag, too? (They are two special classes of relations, that are most frequently taught.)
@MartinSleziak I wasn't sure about the other tag, so I left it and hoped somebody else might have something more decisive. But yes, Willie's explanation of why I appended big-list is correct.