Pitchbend Smoother is a MIDI-only JSFX script that smooths incoming Pitchbend events by slowly going from the previous value to the new value just received, with adjustable randomization and curve shape. Both the shape and the interval can be randomized as well, but only within the range you specify. When using this script, remember that it will introduce lag in the actual pitchbend effects, by its nature. That is in fact very normal for smoothing and is the whole point of it.
For instance, if you have a smooth interval of 500ms, that means it takes half a second to go from current pitchbend to the new pitchbend that was just received. Thus, the "new" pitchbend value will be in effect after half a second, and that's the job of this script: when it sees a pitchbend event, it will smoothly go from the current value to that new one, in the interval specified. If another event happens while it is already in one interval (in other words, for that example, you send another pitchbend event before the 500ms are finished), it will instead go from whatever value it reached towards the new value, in another interval. Without this script, the "new" pitchbend value would be in effect instantly.
For more information and a diagram explaining the curve shape values, visit its dedicated page here.