So it had been roughly 2 years since i remember using this filter so hopefully someone knows what it is. It looks very similar to the cutout filter. However, with the one i remember, there was like a slider at the top that controlled the number of colors in the picture. I hope I am explaining it right. I know for a fact it cant be a long process because i remember finding it randomly but now i can't for the life of me find it. If anyone knows what i am talking about, please help me out. Thanks a lot!!
Image > Mode > Indexed color - lets you adjust from between 3 and 256 colours, but there is no slider.
Some sort of Cartoon effect would do it.
Image> adjustements >posterize?