It appears that last year's Lioness: Hidden Treasures will not be the only posthumous album from Amy Winehouse to be released. Her father, Mitch Winehouse, appeared on BBC 6 recently and revealed that there are numerous leftover tracks that didn't make Hidden Treasures and that the plan is to make one, if not two, more album with that material. You can read his quote on the matter below.
"I'm not sure that there is much more but I'm sure that we will get at least one other album out, if not two. There are loads of covers, loads of them, but the problem is we don't want want to rip anybody off. When her fans are so precious to us we don’t want to put out dross."