For the last few days I have soloed my way through 3 Dice Dungeon Master (DriveThruRPG, 5 pages).
I would describe it as an inexpensive version of Four Against Darkness using one character. I could have played it as it is, but I wanted to “spice it up”. So, I used the thief rules found in Dungeon Crawl Classics, and I used OSR Solo as the solo engine. This PDF does include a link to 3 Dice Dungeon and I recommend that you take a look at that too. So, my thief Char found a dungeon, explored three rooms, found a Tome of Clear Thought, a magic wizard hat, and a small dragon. He killed the small dragon, grabbed the gold pieces, and got the heck out of there. In town, he attempted to pick pocket a businessman, but he was caught by the thieves guild. They forced him to join their guild. Well, they did have a nice place where you could sleep. So, he slept there, got up, searched out of town, and found another dungeon. This one was bigger and had traps and locked doors. He explored eight rooms and found three potions, 12 monsters (he killed them), and more gold pieces. He used the secret tunnel to exit the dungeon. He now is second level and he can use magic. He’s trying to decide how much money to give to the guild. Give this a try!