Weirdly enough, it's been Dash for me if we're talking about highest all time profits.
I remember buying Dash at around $2.00 and selling when it hit like $30, made around 2300 dollars profit that day.
Still had some Dash in my wallet, which I forgot about until I saw that it hit $140, sold all my Dash for 7500 dollars in total, I'd never been so happy that I forgot about something.
LTC has also been very good to me, around 2000 dollars in profit