This is a small client-only mod which lets users change various settings, intended to improve the game's accessibility. I'm autistic and mainly got input from other autistic friends about what features would be helpful, but I am very open to suggestions for future additions! Currently there are four modules:

• Particles - individually define which particles are or aren't shown
  
• Nether portals - the option to turn off the visual effects of standing inside a nether portal
  
• Max brightness - option to force each dimension to display at full brightness
  
• Sounds and subtitles - individual settings for different categories of sound (like hostile mobs, passive mobs, sounds created by your own player, and more):
  • Specify whether the sound plays out loud, displays a subtitle, both, or neither
    
  • Set a custom hex colour of the subtitle if it's displayed
    
  
  

All of the modules are optional and configurable - the default settings leave everything as vanilla.

Github: https://github.com/JayAvery/accesstweaks