This has suffered several structural modifications throughout my experience learning Nix. Inspiration mostly from:

• colemickens/nixcfg
• vimjoyer

• home
  • top-level home-manager modules (per-user)
• homeManagerModules
  • modularised home-manager configurations for apps, terminal and shells
  • profiles
    • not the most ideally named module, but it contains groups of packages that I pretty much use as bundles
• hosts
  • top-level NixOS modules (per-host)
• nixosModules
  • modularised NixOS configurations for apps, services and desktops
  • contains some less modular common configuration
• overlays
  • contains overlays for nixpkgs:
    • local - packages not in nixpkgs, declared locally in packages
    • unstable - the unstable branch of nixpkgs
    • modifications - overrides of nixpkgs packages
• packages
  • local packages
• users
  • user account declarations

• Overriding noto-fonts (and probably other font packages) forces a rebuild of libreoffice. This does theoretically modify the closure, however it is extremely inconvenient.