"Save Selection" feature, or "Selection Banks"
Basically, this feature would allow you to access and store different selections within the timeline. During large edits, selecting multiple video and audio blocks takes time, especially when constructing / deconstructing complex sequences where a selection may include dozens of items throughout the timeline.
Sometimes you need to select one large set, move it, insert another set, then move the original set back into place. The actual selection process here can eat a lot of time, especially since once the selection has been deselected, it must be (and I hate how redundant this is) reselected. It's just a nuisance in larger projects.
It would be very helpful to have a tool or bank where these selections can be quickly saved and accessed.