Ableton's Time Warp tool lets you reshape the timing of percussion notes using a graphical curve, so notes can start spread out, accelerate through the middle, then slow back down, all within the same pattern. It's a way to introduce rhythmic flow and momentum without manually nudging individual notes.
You can apply Time Warp to a full pattern or isolate a selection and work section by section. After warping, three quantize options let you decide what to lock in: the original time range of the selection, the original note end points, or a straight quantize of the result.