My ATmega328p Breakout Board is now open-source! You can get the Eagle files on GitHub.
I will be throwing up more of my PCB designs on GitHub soon too.
I just wanted to leave a quick note that a new through-hole version of the ATmega328p Breakout Board is coming out very soon on Tindie (parts for it will be here next week!). My hope is that this version will be more accommodating to the majority because I know there are those who don’t like surface-mount soldering.