Anastasiy.com does it again. He has brought out a splendid new tool called MixColors I have recently been trying it out and it works a treat. I would recommend reading the manual, as at first glance it isn't how you might expect it to work, but after a a few minutes I was getting into the swing of it.
What I like about this tool to is the fact you an integrate MagicPicker into the panel too which makes it 100% easier to select colours than Photoshops silly colour picker tool. So if you don't already own the MagicPicker tool you should as that alone is worth an investment, it speeded up my work flow. If you need more convincing about MagicPicker I wrote about it in this post here.
If my post still doesn't convince you in buy either of these two products or even just test trying them or even looking at them you should know that a lot of well known studios use these tools like Disney, Marvel, Epic Games etc :)