In the Ocean's 8 movie, Debbie Ocean (Sandra Bullock) has a list of 15 items. The piece of paper is shown a couple of times in the movie. Once, when Debbie and Lou (Cate Blanchett) are sitting in their den, on a table and Lou tries to snatch the list while Debbie swiftly moves it away. Lou says something to the tune of "you can add him to the list".
I guess the him in question is Debbie's ex, the guy she is trying to frame for the heist.
The next time we see the list is towards the end of the movie when Debbie scratches off number 14 from the list.
All items preceding the 14th are already crossed out with only the 15th remaining. My guess is these are plays that she may have learnt from Danny or is her heist bucket list of sorts.
The list seems more likely to be a list of cons. Leaving the 15th item unchecked gives the makers an opportunity to suggest that Debbie is not done yet and there might be a sequel to follow.