My math may be slightly off due to subtracting from a total list which I'm pretty sure is just for the B&N Classics that made it to e-book editions last time I checked, not the full set of paper ones, which have a slightly higher count. Going from the "total" number found in search results on B&N's website can be deceptive for this reason, since they also count some duplicates, IIRC.
I do know that last time I looked, a number of B&N Classics hadn't been converted yet (Dante's
Paradiso being the most glaring gap) but they'd also just added a new batch (including Herodotus'
Histories) to the original 196 or so that were available digitally last year.
ETA: 74 more to go, according to the recount. Full list of not yet offered under the spoiler tag for the morbidly curious.