Humble Bundle has a Delta Green: RPG, VTT & Fiction Collection for $25.

The $25 level is all stuff from a previous bundle so if you have that bundle (which was $18) you don't have to rebuy it for $10 so that's decent of them.

Even though the $15 level is mostly VTT, handouts, and anthologies/novels (less interested in all those) there is still enough RPG stuff to be worth it so I'll buy at the $15 level.

$5 Level

Delta Green: Need to Know (quick start)

Delta Green: The Way It Went Down (anthology)
Delta Green: The Way It Went Down, Volume 2 (anthology)

Delta Green: Extremophilia VTT (Foundry)
Delta Green: Extremophilia VTT (Roll20)

$15 Level

Delta Green Viscid VTT (Foundry)
Delta Green Viscid VTT (Roll20)
Delta Green: Reverberations VTT (Foundry)
Delta Green: Reverberations VTT (Roll20)
Delta Green: Puppet Shows & Shadow Plays VTT (Foundry)
Delta Green: Puppet Shows & Shadow Plays VTT (Roll20)
Delta Green: Music From a Darkened Room VTT (Foundry)
Delta Green: Music From a Darkened Room VTT (Roll20)
Delta Green: Convergence VTT (Foundry)
Delta Green: Convergence VTT (Roll20)
Delta Green: Need to Know VTT (Foundry)
Delta Green: Need to Know VTT (Roll20)
Delta Green: Jack Frost VTT (Foundry)
Delta Green: Jack Frost VTT (Roll20)
Delta Green: Agent's Handbook + The Complex VTT (Foundry)
Delta Green: Agent's Handbook + The Complex VTT (Roll20)

Delta Green Digital Assets: Murder Board Pack 2
Delta Green Digital Assets: Esoterica Pack 1
Delta Green Digital Assets: Classified Pack 1

Delta Green: Through a Glass, Darkly (novel)
Delta Green: Strange Authorities (anthology)
Delta Green: Denied to the Enemy (novel)
Delta Green: Tales from Failed Anatomies (anthology)
Delta Green: Extraordinary Renditions (anthology)
The King in Yellow: Annotated (anthology + Kenneth Hite comments)

Delta Green: Puppet Shows & Shadow Plays
Delta Green: Convergence
Delta Green: Handler's Screen (own)
Delta Green: The Good Life
Delta Green: Dead Letter
Delta Green: God's Hunt
Delta Green: Dead Drops

The King in Yellow Tarot (78 cards + 28-page guide)

$25 Level

Delta Green: Agent Dossiers (own)
Delta Green: ARCHINT (own)
Delta Green: Static Protocol (own)
Delta Green: The Complex (own)
Delta Green: Iconoclasts (own)
Delta Green: Black Sites (own)
Delta Green: The Labyrinth (own)
Delta Green: Control Group (own)
Delta Green: A Night at the Opera (own)
Delta Green: God's Teeth (own)
Delta Green: Handler's Guide (own)
Delta Green: Agent's Handbook (own)
Delta Green: Conspiracy (own)
Delta Green: Impossible Landscapes (own)

Delta Green Evidence Kit: God's Teeth (own)
Delta Green Evidence Kit: The Labyrinth (own)

Delta Green Digital Assets: Public Interest 1 (own)
Delta Green Digital Assets: Law Enforcement 1 (own)
Delta Green Digital Assets: Murder Board 1 (own)
Delta Green Digital Assets: Known Vectors 1 (own)