By RAW, any maneuver that lets you take the attack action, then allows you to replace a weapon attack with eldritch scythe. Of course, eldritch scythe is a melee spell attack, and most maneuvers only benefit weapon attacks. So the scythe won’t get any riders from the maneuver, which is often the point.
Only a few maneuvers actually require a specific weapon attack. Nothing stops a player from blowing 3 exertion to use stunning assault and attacking with a longbow, for example. The ranged weapon attacks just won’t trigger the save-or-stun effect.