When you tap Quick Select you get the following options:
- Select all - all the items will be selected
- Deselect all - all the items will be deselected
- Invert selection - item selection status will be inversed
- Crop selection - items outside the selection will be removed from list
- Select segment - items between the first and last selected will also be selected
- Select non followers - users that don't follow will be selected
- Select user without photo - users that don't have a profile photo will be selected
You can even use Quick Select multiple times to combine two or more.
Example: Select non followers + Invert selection will select all followers.