Here's a couple of my favorite issues of HOUSE OF MYSTERY from 1972. The mystery format began with issue 174, edited by Joe Orlando, one of the E.C. artists of the 1950's, who contributed to the horror line of another era.
Then in 1968-1975, Joe Orlando as editor for DC began to form a new era for mystery titles, revitalizing HOUSE OF MYSTERY and HOUSE OF SECRETS, and based on the success of those titles, expanding that line to include THE WITCHING HOUR, GHOSTS, WEIRD MYSTERY, WEIRD WAR, WEIRD WESTERN, SWAMP THING, PHANTOM STRANGER, The Spectre by Fleisher and Aparo in ADVENTURE COMICS, and many other wonderful creations.

The early HOUSE OF MYSTERY issues are mostly by Bill Draut and Jerry Grandenetti, with Neal Adams doing virtually all the covers from 175-200. Adams did two great interior stories stories in issues 178 ("The Game") and 186("Nightmare"). Wrightson began contributing with issue 179, and the talent pool quickly grew to include Sergio Aragones, Alex Toth, Gil Kane, Tony DeZuniga, Alex Nino, Nestor Redondo, and many others.

The two issues I show above (206 and 207) have opening splash pages by Wrightson, stories by William Payne, as well as stories by Starlin(his first pro work?), Sekowsky/Palmer, Ernesto Patricio, and several other Phillipine artists, in some particularly creepy stories.
Issue 200 shows a characteristic opening splash panel by Kaluta.
Issue 213 displays one of the best covers by Wrightson (a playful twist on a Norman Rockwell Saturday Evening Post cover).

I always loved Cain and Abel as the hosts of their respective titles, and the less explicit nature of DC's mystery stories, as compared to E.C. or Warren.
DC's stories relied on mysterious atmosphere more than shock or gore, combined with charming twists and playful humor, that always resonated more for me. Along with a wide range of very talented artists.

Even after the departure of Wrightson, Kaluta and Adams, the quality of HOUSE OF MYSTERY was consistent up till around issue 260. And even beyond that point, there are many enjoyable issues. Around that point, Kaluta came back and did most of the covers till the series' end.

Even at this late stage, HOUSE OF MYSTERY was a starting ground for many talents such as Michael Golden, Marshall Rogers, Jerry Bingham, Al Milgrom, Bob Layton, Arthur Suydam, Bruce Jones, J.M. DeMatteis, and Mike Nasser. And remained a display case for the talents of Nestor Redondo, Alex Nino, and Alfredo Alcala.