One of my friends, mellonbread, wrote up a dungeoncrawling game. If you follow the blog, you've seen me mention it before. I've been helping him turn it into a complete system by writing up a bestiary. Most of my inspiration was drawn from B/X, though I grabbed some cool monsters from AD&D and other editions and retroclones. A lot of these monsters are people, or rather, humans with class levels.
This poses a particular problem for magic-users, as their spell selections are to be determined randomly. Lots of other games make this pretty easy. A wizard has a number of spells of a certain level that they can cast per day. You consult the table and roll up the appropriate amount of spells. WotC made it even simpler in 5e by giving archmages and priests set spell lists in their statblocks.
However, that doesn't work for Begone. There aren't any spell slots per day of a certain level. It's more vancian than any TSR or WotC edition of D&D ever was. The more powerful you are, the more powerful spells you can hold in your head. This could either by one big spell, a lot of little spells, or a mix of something in between. So how do we decide what "loadout" a wandering wizard has?