In short
Create and Modify all kinds of Adjustment Layers (Curves, Hue/Saturation, Color Lookup, etc.) as big, floating dialogs.
Get it
It’s free, it’s tiny, it’s useful. What not to like.
Floating Adjustments
v.2.0.3
Photoshop 2021+ only
Mac & Windows
1 license, 2 computers
EULA
Free