Colour Balance, RGB Curves and Value Correction, so one can have more control over the general feel of your map. This would help to fit the colourful art style better for darker campaigns.

The already cool filters (Saturation, Clarity, Blue filters,...) would profit a lot from just a little more versatility when it comes to controlling the values of the final picture.

Specifically I am thinking colour balance, which allows you to add/subtract RGB depending on the values of a picture.

I've included a screenshot, that shows how I was able to get a lot more distinguishable lights and shadows by using Value Correction and Colour Balance.

I used colour balance to give the darks more blue-ish hues and the lights more red and yellow hues which did a great job separating the areas!

In the mid tones I just subtracted a little green from the scene. In the end I used tonal correction to add just a little contrast.

And voilá: It is easier readable, more vibrant and I had full control.

I'd love to see this feature in Inkarnate and I'm sure you would love it too :)