The new Humble Borderlands Bundle features all things Vault Hunter. For just a buck, you can score the entire original Borderlands collection on Steam, including the DLCs The Zombie Island of Dr. Ned , Mad Moxxi's Underdome Riot, and The Secret Armory of General Knoxx.
Pay more than the average (which is $4.57 at the time of this writing) and you can collect Borderlands 2 with the added Psycho and Mechromancer along with the Creature Slaughterdome add-on. It also comes with a 75% off Borderlands: The Pre-Sequel coupon, which will knock the price down from $59.99 to $14.99. However, it will be to your benefit to wait a few days for the "More coming soon!" to be filled in at this tier.
At the highest tier at $15 or more, you will nab more add-ons for Borderlands 2 which includes the Ultimate Vault Hunter Upgrade Pack 2, Headhunter 5: Son of Crawmerax, and the Season Pass. It also comes with a 25% off coupon for merch at the 2K Store.
For this Humble Bundle, you can split your money to give proceeds to the National Videogame Museum.