American 2-way switches (3-way in U.S. terminology) have unlabeled toggles though.
Only simple 1-way switches have "On" and "Off" marked on the toggle.
Same here. One old series of toggles had a red dot for "on", the 3-way and 4-way were just white (by the way, in German 3-ways are call alternating and 4-ways cross switches, because they alternate between the two travellers resp. cross out the travellers).