omg once upon a time i had 500 ZCL, and they didn't move much, and i sold them... now look...i wanna cry.
Happens to a lot of people, just consider it an expensive lesson. Back in the days I had a good chunk of MINT coins. Due to no further development, the price went down to 1 satoshi and I sold them all. After few months the development re-started and it went up to 30 satoshi. So I know how you feel. Also look at the people who sold XVG really cheap (not really a fan of XVG myself, just giving an example).
The lesson I learned is that you should not sell anything if it becomes worthless (It isn't going to give you good money selling it dirt cheap anyways). Just keep it into backup drive and forget about it. Who knows what will happen in future?