Hello! Yeah, we'd love to add contrast as an effect eventually. As for Voxelorama, it does indeed work in 1.0 and you can download it easily by going to Edit > Preferences > Extensions > Explore Online. Enabling it adds a new tool and an option to the Image menu. If the option in the Image menu is not working, it probably means that you have an old nightly version and need to re-download, as this was recently fixed.
Thank you for the response! Bummer about contrast, but I just tried out Voxelorama with a new nightly build, and it really works, thanks! Looking forward to seeing more from this tool. I just wanted to add that Overwrite Color in the Pencil tool and the Shading Tool are my absolute favourite tools in this app! I also like how your undo feature works, how it ignores some changes like layer opacity or some things that can easily be changed with a slider. It's a small thing, but it really helps my workflow, so please never change it! Overall, this has become my favourite pixel art app. Thanks for all your hard work!