The Open Hand's Free Rider
In D&D 5e, the Way of the Open Hand’s first feature is Open Hand Technique. When you hit with one of the attacks granted by Flurry of Blows, you can impose one of three effects. The claim that these bypass saving throws is only partly true. The prone and push options force a Dexterity or Strength save. The third option, blocking a target’s reactions until the end of your next turn, does not.
The value is not that the rider is free of saves. The value is that it rides on Flurry of Blows, which you were spending a ki point on regardless. Two attacks, and each hit is a chance to knock prone (granting your allies advantage), shove ten feet, or lock down a caster’s Shield and Counterspell for a round. You pay nothing extra beyond the ki already committed.
Treating this as an occasional trick wastes it. The prone effect in particular compounds: a downed enemy gives every melee ally advantage before it stands.
At the table: On your Flurry, drop the biggest melee threat prone, then let the fighter and rogue swing with advantage before it can rise.