u/Individual_West_1670

I ran $ nix registry list and it listed these flakes:

global flake:agda github:agda/agda  
global flake:agenix github:ryantm/agenix  
global flake:arion github:hercules-ci/arion  
global flake:blender-bin github:edolstra/nix-warez?dir=blender  
global flake:bundlers github:NixOS/bundlers  
global flake:cachix github:cachix/cachix  
global flake:composable github:ComposableFi/composable  
global flake:disko github:nix-community/disko  
global flake:dreampkgs github:nix-community/dreampkgs  
global flake:dwarffs github:edolstra/dwarffs  
global flake:emacs-overlay github:nix-community/emacs-overlay  
global flake:fenix github:nix-community/fenix  
global flake:flake-parts github:hercules-ci/flake-parts  
global flake:flake-utils github:numtide/flake-utils  
global flake:helix github:helix-editor/helix  
global flake:hercules-ci-agent github:hercules-ci/hercules-ci-agent  
global flake:hercules-ci-effects github:hercules-ci/hercules-ci-effects  
global flake:home-manager github:nix-community/home-manager  
global flake:hydra github:NixOS/hydra  
global flake:mach-nix github:DavHau/mach-nix  
global flake:ngipkgs github:ngi-nix/ngipkgs  
global flake:nickel github:tweag/nickel  
global flake:nix github:NixOS/nix  
global flake:nix-darwin github:nix-darwin/nix-darwin  
global flake:nix-serve github:edolstra/nix-serve  
global flake:nixops github:NixOS/nixops  
global flake:nixos-anywhere github:nix-community/nixos-anywhere  
global flake:nixos-hardware github:NixOS/nixos-hardware  
global flake:nixos-homepage github:NixOS/nixos-homepage  
global flake:nixos-search github:NixOS/nixos-search  
global flake:nixpkgs github:NixOS/nixpkgs/nixpkgs-unstable  
global flake:nixvim github:nix-community/nixvim  
global flake:nur github:nix-community/NUR  
global flake:patchelf github:NixOS/patchelf  
global flake:poetry2nix github:nix-community/poetry2nix  
global flake:pridefetch github:SpyHoodle/pridefetch  
global flake:sops-nix github:Mic92/sops-nix  
global flake:systems github:nix-systems/default  
global flake:templates github:NixOS/templates

Where are they coming from exactly? In my flake I only specify Agenix, Stylix, NixVim and Home-manager. I've read the manual page and this post, but my only takeaway is that you can run things like $ nix run nixpkgs\#hello.

I've also seen people disable the registry with nix.settings.flake-registry = ""; in their NixOS configuration. Is there any downside doing this?

My flake.nix.
Thank very much.