Operation Unfathomable is a super-fun, gonzo OSR underground wilderness crawl by Jason Sholtis.
I’ve run it a few times using the Black Hack OSR rules set. The book comes with ten pregenerated characters for Swords & Wizardry and other old-school D&D-style RPG.
To make it easier for myself, I took the characters and converted them to match the Black Hack rules a little more closely. I’m posting it here for anyone who might find it useful. Here’s the PDF with a sheet for each character, and a GM sheet with the basic stats for each character:
At the beginning of the adventure, the players are offered a list of magic items. I’ve made a PDF list of the items, each converted to the Black Hack rules, along with a conversion of a new spell from the adventure.