snowynight

Ironsworn is probably one of the most popular solo tabletop RPG, and it's free. (It can also be played wth or without a GM). You play heroes going on perilous quests in a harsh low fantasy land. You can customize the setting by answering a set of guided questions with chosen details. The character generation is simple. The way for characters to advance is to swear an Iron Vow and face challenge to progress, which really help directing the gameplay. There are robust tools to help you when you feel stuck.

List of free Ironsworn tools
Ironsworn character generators

Character:

Stats

Edge 3. You are nimble, fast, and precise.
Shadow 2
Wits 2
Hearts 1
Iron 1

Assets

Rider (Path)
Spirit-Bound (Path)
Sway (Ritual)

Background Vow: You have sworn upon iron vow to rebel against power (action: defend, theme: creature).

Inciting Incident: Presently, you Swear an Iron Vow to address a problem: dangerous discovery (action: search, theme: love).

Person of Interest: Makari, an athletic, insensitive, and passive performer, whose goal is to protect a secret.

Bond 1: Deepwater, an empty, civilized, and rich settlement located in the Barrier Islands.
Bond 2: Griff, a critical, clever, and timid adventurer, whose goal is to secure provisions.
Bond 3: Joa, an affectionate, adventurous, and timid forester, whose goal is to collect a debt.