For the particular style you seem to be looking for, I think Earthdawn could be worth a look. It's not level-less, but it sort of reverses the way levels work.
Each character has a Discipline, which is basically the equivalent of a class (it is possible but expensive to have multiple Disciplines). The main benefit to a Discipline is having access to a number of Talents, which both cover bread-and-butter abilities like Melee Weapons or Spellcasting and more interesting special abilities like Taunt, Acrobatic Strike, or Fireblood. As you adventure, you gain Legend Points (XP), which you spend on increasing your Talents (and possibly your stats). Once you have increased them enough, you qualify for the next Circle (level), and once you train you will get access to two new talents: one fixed and one chosen from a list.
This means you can still use level (circle) as a rough guide to how powerful a character is, but there's quite a lot of flexibility in how you develop your character.
Outside of that, there are many, many different level-less games. Generally speaking, few of them allow characters to become as world-shaking as high-level D&D characters, but that's not inherently a feature of level-less games, just a common trait.
Each character has a Discipline, which is basically the equivalent of a class (it is possible but expensive to have multiple Disciplines). The main benefit to a Discipline is having access to a number of Talents, which both cover bread-and-butter abilities like Melee Weapons or Spellcasting and more interesting special abilities like Taunt, Acrobatic Strike, or Fireblood. As you adventure, you gain Legend Points (XP), which you spend on increasing your Talents (and possibly your stats). Once you have increased them enough, you qualify for the next Circle (level), and once you train you will get access to two new talents: one fixed and one chosen from a list.
This means you can still use level (circle) as a rough guide to how powerful a character is, but there's quite a lot of flexibility in how you develop your character.
Outside of that, there are many, many different level-less games. Generally speaking, few of them allow characters to become as world-shaking as high-level D&D characters, but that's not inherently a feature of level-less games, just a common trait.