There are great resources for a Linux distribution maintainer and here are a few of my favorite. Most sources are geared towards Ubuntu based systems but a few like the Themes and Window Managers links are more or less universal.

Window Managers

The first site deals with the plethora of window managers that are out there. XWinMan lists many managers ranging from session and full desktop managers to just the bare windows themselves. There are some that are deprecated so be weary; but, it still has many that are not!

              Link:  http://www.xwinman.org/

Source List Generator

The next is a site that generates source list files for Ubuntu. This is really awesome for a number of reasons but the biggest for me is recovering from a bad dependency hell scenario. While it is rare, it is something that a maintainer and even a user needs to be aware of. Adding too many PPAs (which generally isn't recommended) can cause loops and other strange and unexpected behavior from a package manager. In addition, the generator gives PPA info on a number of popular software this is not necessarily shipped with the system. It is well worth keeping in ones developer/user arsenal.

              Link:  https://repogen.simplylinux.ch/index.php

Themes

This third link deals with themes, icons, backgrounds, etc. Who doesn't like themes? Anyway, it has many of these to spruce up the system and make it less boring. I started using Gnome-Look early on in my Linux experience and it has yet to fail to find me something cool or aesthetically pleasing.

              Link:  http://www.gnome-look.org/

Debootstrap Versions

This fourth link is geared towards building a Debian based distribution. Debootstrap is a great peace of software but needs the PPAs of the system it will setup in a subdirectory of ones system. This links provides the needed information.

              Link:  http://packages.ubuntu.com/search?keywords=debootstrap&searchon=names&suite=all§ion=all

Ubuntu-Mini-Remix

This fifth link goes to a website that has minified Ubuntu ISOs. These are phenomenal for creating new distributions from pretty much scratch. It isn't LFS kinda scratch but it's as close as it's likely to get.

              Link:  http://www.ubuntu-mini-remix.org/

Chrooting in and building up is the best way to do this. I have a video of the steps too:

Package List

This last link is great for doing source compiling. This can be used to find the install name of a package when an error output doesn't give much of a hint. I must admit I only just recently heard of this page after attempting to compile a installer package. Going to the IRC of the developer was where I learned of this. It's a bit embarrassing for not having known of this given how long I've been using various *nix systems. Still, I guess the old adage, "you can't teach an old dog new tricks", is proven wrong.

              Link:  http://packages.ubuntu.com/