I write digital gamebooks for 5e. They're similar to solo adventures of past editions, but updated to allow you to play in your browser. You can use any appropriately-leveled 5e character. The game handles telling the story, rolling enemy dice, and setting DC's for your actions.

The Saint's Tomb

Jump into the life of a first level adventurer with an exploration of The Saint's Tomb. A notice, pinned to the wall of a temple, calls you to adventure "If you can defend yourself and wish to defend the cause of righteousness, please apply within." Will you explore the dangers of the saint's tomb and unravel the mysteries held within?

A Miner Problem

Arriving in a small town in the mountains, you're hired to retrieve a crazed engineer who has barricaded himself in the gem mines of a powerful owner. The locals miners have their own views on how the mine is being run. You'll have to delve a bit deeper in this 2nd level adventure for one player.

5e Arena

5e Arena is a pit-fighting game based on the rules of the RPG that's synonymous with fantasy adventure. Playing as a character between levels 1-5, you can choose the rank of competition, then battle against three foes back-to-back to win fame, gold, and perhaps more.