Spoiler warning: Players in my campaign, this is the map for the dungeon under the old oak tree, which your characters long explored. I guess you most likely won't go back there, but still I'd suggest not looking at the map, and especially not reading the key, as I think this would spoil some of the magic, so to speak.
Inspired by a comment from Brendan on an old post of mine where I shared a dungeon map I'd drawn, I thought I'd post another map, and the accompanying key for it. The map you see is actually the first level which leads down to the map I posted previously. The latter was only partially stocked, and the party never ventured into it, so it remains unfinished and unexplored. The 1st level was however almost fully cleared out, explored over the course of probably almost a dozen play sessions -- I'm really surprised how long it lasted!
So here's the map, and the first part of the key, typed up from the notes I used to run it. The notes are very rough, so a dash of imagination is required while reading! Still, I hope it proves entertaining, interesting and / or useful for someone. I'll post the rest of the key as I find time to type it up.
The Dungeon Under the Old Oak Tree
1. A large glade in a forest. Huge oak tree in middle, hollowed out. Shaft leads down. Sides of shaft covered with tree roots, like ladder. 1 in 10 chance to fall. Sandy floor at bottom, walls still riddled with roots. One root has "NOLLY'S KINGDOM" carved into it.
1a. Roots covered in moss, crawling with worms & insects. Old leather glove laid over root (left). From east comes whooshing sound. Faint glow and warmth from south.
2. In passageway tree roots reach out to grab items from PCs as they pass. If anyone fails a DEX check they lose an item. Can be recovered by cutting the roots -- at which an ominous rumbling is heard.
3. Muddy floor, mossy walls (glowing). Three 5' deep nooks. One has cosy cloaks & coats (in pocket of one is key to 28). One has a portrait of a gnome-like creature. One has a hat stand with red & purple felt hats.
4. Low round roof. Round cobblestoned floor. Neat wooden table & chair. Small bell and plaque "PLEASE RING". Walls still mossy & rooty.
5. Bookshelf full of nonsense. Sack of bones behind bookshelf. Two comfy upholstered chairs. Chairs attack if touched: AC 7, HD 1 (5, 6hp), Att
2 x 1d3 (clawed arms). Books fly out.
6. Cute kitchen. Sheep-headed faun called "Ramius". Acts all Mr Tumnus but tries to feed PCs sleep tea (save vs spells) and then eat them. AC 6, HD 2 (12hp), Att butt 1d6, knife 1d6.
7. Ramius' lair of horror. Skulls & bones. Chest with fresh human remains and 87gp, 192sp, 202cp, sapphire worth 400gp. Four sheep skulls which Ramius can command: AC 8, HD 1 (4hp each), Att 1d6.
8. Cobblestones. Round roof. Door carved with tree motifs. Large red patterned rug, concealing magical circle. Teleports to 32. 2 in 6 chance of stepping on rug by chance.
9. Stone walls. Small table with glass jars. Inside are tiny dead people (1" high). Two scrolls -- one of MU spell reduce, one (written in fey tongue) a page from a story about a journey to another world of micro-people.
10. Stone. Statue of two dogs and their master, a hunter. Mirrors on west & east walls, anyone looking in sees the hunter's face instead of their own, mad look in his eyes. Hear barking and a horn somewhere distant. Each turn 2 in 6 chance of being attacked. Hunter: AC 6, HD 2 (10hp), Att 1d6 + 1 (axe). 2 x dogs: AC 7, HD 1 (3, 5hp), Att 1d6 (bite). Hunter has a pouch of ancient silver coins (300sp), worth five times normal value to a collector.
11. Archway formed of serpents. Giant crab spider lurks. AC 7, HD 2 (8hp), Att 1d8 + poison, 1-4 surprise.
12. Decrepit statues of ancient kings. Old leather boot rests behind one (left foot). Chalk arrow drawn by south-east door. Rotten stench coming from 13 / 18. (There may be a troglodyte in this room.)
13. Three troglodytes. One is bigger then the others and bullies them. Fish hanging from ceiling. Piles of fish bones. Never sleep. Either here or at the river or prowling in 12. AC 5, HD 2 (12, 7, 8hp), Att 3 x 1d4, F2, 1-4 surprise, stench. Secret doors: buttons hidden in giant gawping face carvings.
14. Giant fish skeleton hanging. Pile of trash -- clothes, leather, rusted weapons. Small wooden chest (trapped, save vs poison or die in 1 turn), contains: 492gp, 1017sp, 128ep, silver bracelet (200gp).