My best investment is matrixchain. I remember that i invested matrix with my 5 ether during crowdsale 1 phase and after matrix hitted 5x i think and i sold all of my coins and accumulate from dip again and i sold again . Now i am holding only ethereum for now. But matrix chain was my best investment in 2018. Yes maybe i didint earn 50x money but at least i earned something. I am sure there is some investors which earned 50x or more .