So HSXsanity has put together a table of midnight box office estimates for over 100 movies, which you can access at this link.
The table aims to be as comprehensive as possible, but comprehensive information on midnight box office is not always available - and even if information is available, it has not always been 100% accurate. However, the data should still be good enough to be workable.
Most of the data in the table is sourced from articles on boxofficemojo.com or other media like Deadline, EW and THR. You can check the source of the information yourself by following the relevant link in the 'Source' column. However, some information is inferred from more recent reporting, and other data is estimated from posts on the Movies board giving inside information and is not sourced. This is also indicated in the 'Source' column.
And this data is really only useful if when it is interpreted correctly. For some thoughts on how to do that, check out this column.