What are some nice snippets that everyone should have in their NixOS config?

Nix-specific shell aliases: nixls is 'cd /etc/nixos && tree *.nix(wrong tree syntax hut you get the gist)nixrs` is a function that...

• runs git add . and git status in /etc/nixos
• runs nixos rebuild-switch --flake
• returns you to whatever directory you were in

lib.mkIf for optional configs

Using let ... In {} more often, basically treating nix as a programming language instead of a config language

I like to include memtest in my boot menu:

boot.loader.systemd-boot.memtest86.enable = true;

You can also use it with grub:

boot.loader.grub.memtest86.enable = true;