Meg: Vol. 2.1 (Swimming in Blood)

In early 1992 (as prog 780 launched the much-hyped Megablast jump-on) the Megazine re-launched as the fortnightly Volume 2 and a few weeks later we got the first direct crossover-thrill in the form of the Judge Dredd mega-epic Judgement Day (featuring special guest star Dennis the Menace). That sort of sums up this era: on the one hand we get amazing new content (Devlin Waugh, Dredd teaming up with Alpha) and on the other there's a sort of childlike spattering of colorful paint across the walls of the living room while nobody's looking (in the form of a zombie-apocalypse-musical that leaves a bewildered Dredd looking on and trying to look taciturn).

Judge Dredd
The major event here is the mega-epic Judgement Day, running concurrently in the prog and the meg (the latter for each third episode), and so floating in at twenty episodes, four artists and 150 pages of pressure to purchase both publications. Ennis ladles it on by making it a globe-trotting, multi-Meg, multi-Judge-force adventure to save the planet from an unstoppable zombie horde consisting of everyone who's ever died. Mix in a pontificating stage villain (Sabbat the Necrophagus) who keeps Dennis the Menace as a pet and likes to put on musical stage shows for his captives, and you end up with an odd blend of deadly threat and camp spectacle.

Clearly in need of some grit, Johnny Alpha is teleported in from the future (inspired by 1990's Top Dogs story in the 1991 Judge Dredd Annual) as Dredd buys some time by nuking three of the world's Mega-Cities, at the loss of two billion lives. The climax is Carry on Dirty Dozen before Dredd and Alpha swagger off into the (apocalyptic, highly radioactive) sunset for all the world like Rooster Cogburn and Jesse Custer.

The prog and meg disentangle themselves, with the next crossover waiting until 1994...

Devlin Waugh: Swimming In Blood [NEW THRILL]
One of the best character introductions of all time: this presents the titular toff as (in the author's words) "Noel Coward played by Arnold Schwarzenegger", a "spiritual envoy" working for the vatican in Dredd's world. We meet him as he is sent to Aquatraz (an underwater prison in the shape of a seahorse) to tackle a vampire incursion.
Our next meeting with Devlin is fleeting as we get a Brief Encounter in 2.26...

Armageddon: The Bad Man [NEW THRILL]
Borrowing heavily from Terminator, Total Recall (literally lifting the "Open your mind!" scene) and, uh, The Bible, this derivative slice of action pie enigmatically ends on a cliffhanger without fully explaining itself. There's a hint in Meg 1.19 that this is going to explain the origins of Mega-City One, but it never explicitly does that, instead telling us of a shadowy organization using global destablization as an excuse to grab power (while a psychic runs away from a mysterious assassin).
Tis one and done, as per the contractual shenanigans.

Soul Sisters [NEW THRILL]
An avant garde, campy, technicolor romp set sixty-two years beyond the Dredd timeline in Brit-Cit: the Soul Sisters are a pair of handy (in a fight) vigilante nuns. I can't tell you the plot beyond that because however many times I sit down to read it, I find myself losing the will to live and then my id autopilots me onto something less lethal. In the 1993 Judge Dredd Yearbook The Dark Nuns Return has the Sisters come back from the grave to help a Brit-Cit that has been plunged into hell by, erm, John Major.
And that's it for the Soul Sisters. You may thank God in His mercy (or the two Daves who stopped writing it). Or maybe you loved it, in which case I apologize.

Anderson, Psi-Division
The 1992 Judge Dredd Mega-Special features the tragic two-part Baby Talk, in which a narcotic ingested by a pregnant addict gives her embryo psi powers. Meg 2.08's Blythe Spirit sees an insanely tortured soul set loose on a packed block. It's notable for two things: Anderson is continually followed around by a wind machine (because it's David Roach on art) and the climactic line is "Kill the chicken!" George (in the 1993 Judge Dredd Yearbook) is a weak-sauce, one-note joke strip about a satanic tapeworm (called George).
Anderson continues into the next Meg stage...

Judge Hershey: Downtime
The second solo outing for Hershey (since 1989's Mega-Special) sees her dealing with a violent drug outbreak at her local gym. (Yes, there is exposition explaining why she's at a local gym as opposed to a Justice Department facility.)
Hershey has more tales in the next Meg stage...

Special Mentions:

Red Razors
The 1992 Judge Dredd Mega-Special regales us with The Secret Origin Of Comrade Ed, in which we discover that Ed got deliberately transformed from human to sentient horse in order to escape an ugly girlfriend with a psycophathic father. The 1993 Judge Dredd Yearbook has Razors take on a gang of homicidal medical men in the risible Doctor's Orders.
A second series of this ... thing ... transits from the Meg to the prog in 1994...

The Straitjacket Fits: The Final Fit - The Relapse (1993 Judge Dredd Yearbook)
A follow-up to the Megazine's Volume #1 comedy, this provides a self-referential, self-confessed lack of resolve whose most impressive moment is a riff on Arkham Asylum (McKean & Morrison, 1989).
The sub-title speaketh true, and this is indeed the last of this.