Doom 1&2 BFG Edition, Heretic, Hexen: Beyond Heretic (with Deathkings of the Dark Citadel) IWADS

Doom 1&2 - BFG EDITION(doom.wad | DOOM2.wad | NERVE.wad)
The ruins of an ancient Martian civilization have unlocked the secrets to teleportation, and the UAC will stop at nothing to harness this world-altering technology.

As part of a marine detachment sent to protect the facility, your duty seemed simple enough... until the invasion. Now, in an epic clash against pure evil you must fight to understand who is with you, who is against you, and what must be done to stop this nightmare from reaching earth. This only comes with the BFG Edition WADS.

Heretic(heretic.wad)
Three brothers, known as the Serpent Riders, have used their powerful magic to possess seven kings of Parthoris into mindless puppets and corrupt their armies. The Sidhe elves resist the Serpent Riders' magic. The Serpent Riders thus declared the Sidhe as heretics and waged war against them. The Sidhe are forced to take a drastic measure to sever the natural power of the kings destroying them and their armies, but at the cost of weakening the elves' power, giving the Serpent riders an advantage to slay the elders. While the Sidhe retreat, one elf (revealed in the sequel to be named Corvus), sets off on a quest of vengeance against the weakest of the three Serpent Riders, D'Sparil. He travels through the "City of the Damned", the ruined capital of the Sidhe (its real name is revealed to be Silverspring in Heretic II), then past Hell's Maw and finally the Dome of D'Sparil.

Hexen: Beyond Heretic(hexen.wad)
Following the tale of D'Sparil's defeat in Heretic, Hexen takes place in another realm, Cronos, which is besieged by the second of the Serpent Riders, Korax. Three heroes set out to destroy Korax.
Deathkings of the Dark Citadel Expansion (HEXDD.wad)
Deathkings of the Dark Citadel is the official expansion pack that was released for Hexen in 1996. It features three more hubs with a total of 20 new single player levels and six new deathmatch levels. Unlike the Shadow of the Serpent Riders expansion pack for Heretic, it had to be purchased in retail stores or by mail order. This was unusual at the time, as most non-free expansion packs also included other new or revised gameplay elements. This expansion pack also did not initially include nor enable any music.