Lasso Tool For Frame Selection in Timeline
A lasso tool for selecting frames on the timeline would be fantastic for speeding up retiming of repeated/offset animation fx.
Lots of times you will have multiple objects with the same animation but offset a few frames, this results in frames organized at a diagonal on the timeline which isn't so easy to select with a box selection.
If you need to have an example of software that can do this. Blender actually has lasso selection for keyframes in the **** Sheet editor, it's extremely helpful.