Researching the eBay prices the titles you do have will have given you a rough idea whether it's better to sell them singularly or idividually (compared to the probable lower end price but less investment of time for selling them as a bulk lot).

Personally, I'd go to a Nintendo enthusiast's site and see if anyone is willing to provide some (hopefully unbiased)  insight as to the desirability / rareness etc of the titles you can't otherwise research, or at least point you in the right direction to research the pricing. If it turned out there were just a few gems and the rest were so-so (in terms of desirability / value), I'd list the gems separately and probably the rest in either one big lot or a couple of smaller ones.

The alternative is to just list them individually at auction and see what happens...