Voting Systems without tactical voting Which voting systems do not have tactical voting? Specifically, expressing your true preference on a ballot will not result in a less favorably outcome. I'm looking at both multiple-winner and single-winner. One that I know off already is random ballot, and dictatorial.

By Gibbard–Satterthwaite theorem, any resolute voting rule that satisfies Pareto and which is non-manipulable (i.e. doesn't have tactical voting) is necessarily a dictatorship. See theorem 3.1.2 in _Social Choice and the Mathematics of Manipulation_ by Alan D. Taylor.