Rasmus Morgenstern, Wizard extraordinaire, was fond of riffing on the effects of existing spells, creating alternate versions of popular standards. He also created several wholly original, if a bit quirky, spells and collected the personal spells of like-minded colleagues.
Resnet Morgenstern, Bard of no small renown, was a lover of knowledge who travelled extensively and amassed her own large collection of rare and unusual spells.
These spell books are intended for use as “random” treasure items, or perhaps as the centerpiece of a main villain’s library. Alternately, individual volumes could be placed as treasure and a quest line built around finding them all. And of course, they can simply be used as a ready source of a-la-carte spells for your campaign.
The Morgenstern Family Papers are available as “pay what you want” exclusively from DriveThruRPG.