all is here https://docs.unity3d.com/ScriptReference/QualitySettings.html ?
No, not everything is there and a lot of stuff there is not relevant unless you have actually spent the effort to use those features in your game. There is no such thing as “all the options”. Every time you use any Unity API or feature it could potentially be customized using an option, every time you add a new feature to your game it could potentially be controlled by option. A lot of stuff will vary between games because: not all the games use all the features of engine, implementing certain functionality is up to the game developer, certain features can be used in different ways and combinations, certain features can be implemented using different approaches, some features require extra packages and manual work to implement. Changing Unity QualitySettings will have no effect if you have your own custom implementation for corresponding graphics effect. Exposing settings for Unity features which you don’t use will only make the players frustrated due to the options not doing the thing they claim and having to waste time searching for settings which actually work.
If you have to ask question like this then most likely it will be a lot more valuable for the players if you implemented good: resolution and scaling settings, volume controls, input rebinding, accessibility, UI and gameplay settings. All of those are more or less dependent on the game with no single best or correct solution. Resolution and scaling behavior will depend on how flexible you made your UI (flexible UI is up to you), and the art style (nicely scaling pixel art is not the same as resizing window with 3d graphics), your chose of Camere components and how you use them, any nontrivial graphic pipeline and rendering passes for implementing special effects. Volume controls will depend on how complex sound system you setup and how finely you group your sound effects. Input rebinding will depend on how you read it (old input, new input, rewired, your own abstraction layer on top of any of the previous) does your game have local multiplayer modes, what kind of input devices does your game support? Stuff like hiding extra UI elements or finetuning UI size and positioning is up to you.
Even if you consider only graphic quality settings a lot of stuff is up to developer. Unity can’t know which parts which parts need higher resolutions textures more and which parts are less critical. It is up to you to create lower level 3d meshes and deciding which ones are fine to hide at distance. If you are writing fancy shaders it is up to you to write simplified versions of them and decide and when to use them.
