Humble Bundle's Doctor Who RPG Book Bundle is very similar to a Bundle of Holding package I bought last year.

I already have these items from my previous purchase

• Doctor Who RPG (12th Doctor Edition)
• The Time Traveller's Companion
• Defending the Earth: The UNIT Sourcebook
• The Gamemaster's Companion
• All the Strange Strange Creatures vol 1
• The Silurian Age
• All of Space and Time vol 1
• Paternoster Investigations
• The Black Archive
• The First Doctor Sourcebook
• The Second Doctor Sourcebook
• The Third Doctor Sourcebook
• The Fourth Doctor Sourcebook
• The Fifth Doctor Sourcebook
• The Sixth Doctor Sourcebook
• The Seventh Doctor Sourcebook
• The Eighth Doctor Sourcebook
• The Ninth Doctor Sourcebook
• The Tenth Doctor Sourcebook
• The Eleventh Doctor Sourcebook
• The Twelfth Doctor Sourcebook

These are new items I don't have, along with their DriveThruRPG PDF prices

• Doctor Who RPG (10th Doctor Edition) ($30)
• Doctor Who RPG (11th Doctor Edition) ($30)
• Doctor Who: Aliens and Creatures ($25)
• Ravens of Despair ($3)
• Medicine Man ($3)
• Cat's Eye ($3)

$18 for the whole bundle doesn't seem worth it to me, especially since I assume the 10th Doctor and 11th Doctor edition RPGs are much the same as the 12th Doctor edition.

Actually all the new stuff is covered in the mid-tier ($10) bundle so that's worth it enough. The $1 tier has the 10th Doctor edition RPG plus the three adventures so best bang but I'm fine paying $9 for two more items.