Selections have hotkeys, but they are arcane in comparison to industry standards.

Current defaults:
ctrl+a: select everything
ctrl+shift+a:deselect everything
a: switch to add mode.
s: switch to substract mode
i: switch to intersect.

Default hotkeys:
ctrl+a : Select everything.
ctrl+d : deselect everything.


Sticky keys:
Most software has sticky keys to switch between the add/substract/intersect selection.

This is in Photoshop:
Shift: Add
Alt: Substract.
No selection+ Shift: Selection has perfect 1:1 ratio(square or circle).
No selection+ Alt: Selection grows from center.
No selection+ Alt+Shift: Combination of above functionality.

This is in Gimp:
Shift: Add
Alt: Move selection.
Ctrl: Substract.
Shift+Ctrl:Intersect.
Pen down+ Shift: Selection has perfect 1:1 ratio(square or circle).
Pen down+ ctrl: Selection grows from center.
Pen down+Ctrl+Shift: Combination of above functionality.

This is in Paint.net:
Ctrl: Add
Alt: Substract.
Alt+RMB: Overlapping Intersect(difference).
Ctrl+RMB: Inverted Intersect(regular intersect).
Shift: Selection has perfect 1:1 ratio(square or circle).

We already have sticky keys for 'alternate tool invocation' and 'change primary setting'. We'll need to puzzle to have these align with industry standards.

Reproducible: Always