The Forgotten Crypt of Queen Gilaren is a 2-page dungeon adventure module for Old School Essentials (by Gavin Norman).

It includes a detailed map with 14 rooms ready to venture through. Every room has something to interact with. Into the dungeon there are puzzles and combat encounters. It’s doable with a small party of 3 to 4 characters of 1st or 2nd level. Could be a little mean, but hey! It’s Old School.