Next month will see the release of Unbroken: Path to Redemption, the follow-up to Angelina Jolie’s 2014 biopic of Olympian-turned-PoW Louis Zamperini. Considering how successful the first Unbroken proved (it grossed $163m off a budget of $65m, with the third largest Christmas Day opening ever) you might be wondering why this sequel isn’t getting more attention. The answer is simple: it isn’t an official sequel. Aside from producer Matt Baer, none of the original cast or crew are returning for the new film, and Pure Flix, the faith-based distribution company behind the film’s release, hopes that brand recognition alone will be enough to draw audiences.

Iffy as such a marketing campaign may sound, Unbroken: Path to Redemption actually fits into a long tradition of unofficial sequels – films attempting to capitalize on popular properties despite having no actual connection. It’s a bizarre subgenre mostly filled with cheap knockoffs, ignored or forgotten by all but diehard completists and tapeheads. However, within this cinematic outland, there are more than a few diamonds in the rough. Here are some of the more notable entries in the canon of motion-picture apocrypha:

Casino Royale (1967) and Never Say Never Again (1983)

The only two James Bond films not made by Eon Productions, each of these entries, though adapted from Ian Fleming novels and featuring the iconic secret agent front-and-center (portrayed by David Niven and Sean Connery, respectively), are generally considered to stand outside the series’ established continuity. That’s an easy enough designation when it comes to Casino Royale, as it is as much a spoof as it is spy thriller, but Connery’s return to the role after a 12-year absence is harder to dismiss, especially since what it all boils down to is petty squabbling between rights holders.

Zombi 2 (1979)

Thanks to loose copyright laws, Italy is the greatest source of unofficial sequels. Italian producers have long exploited this system, generating countless knockoffs of American movies – especially American horror movies – oftentimes attempting to pass them off as legitimate sequels. While most of these movies turn out about as shabby as you’d expect, one particular example stands out from the rest: Zombie 2, Lucio Fulci’s provisional sequel to George Romero’s Dawn of Dead (reedited by legendary horror maestro Dario Argento for Italian audiences, and retitled Zombi 2).

The film attempts to tie itself to Romero’s original film with two quick bookends, but otherwise it’s all Fucli’s show, a grand guignol maelstrom, overflowing with visual and sonic flourishes, faint-worthy bodily carnage and a suffocating air of cosmic dread. As if that weren’t enough of an endorsement, there’s a scene where a zombie fights a shark underwater.

The Return of the King (1980)

Twenty-three years before Peter Jackson brought his epic Lord of the Rings trilogy to a close (or so we all thought), smashing box office and Academy Awards records alike, there was this television production from animation studio Rankin/Bass. A very truncated version of JRR Tolkien’s concluding novel, the movie is a continual source of confusion: while many viewers assumed it to be a direct continuation of Ralph Bakshi’s roto-scoped adaptation of the Lord of the Rings two years prior, it was actually meant to serve as the follow up to the beloved 1977 animated version of The Hobbit. Out of the three, The Return of the King is the least memorable, but at least it afforded Tolkien nerds some measure of closure at a time when the notion of any legitimate adaptation seemed utterly impossible.

Hello Mary Lou: Prom Night II (1987)

Returning to horror, Hello Mary Lou: Prom Night II is opposite from most unofficial sequels – while it’s technically part of the larger franchise, it has zero connection to the other films beyond its tacked-on subtitle. Conceived and produced as an entirely original film, The Haunting of Hamilton High was renamed in order to capitalize on the success of the first Prom Night.

Unlike its by-the-numbers predecessor, Hello Mary Lou is a legitimately compelling movie, a tightly constructed supernatural thriller with a handful of clever set pieces and bursts of startling artistry. Mostly forgotten since its release, the film has received critical reappraisal over the last couple years, giving it a reputation as The Godfather 2 of 1980s slasher flicks.

Troll 2 (1990)

Often held up as the best worst movie, Troll 2 is another Italian production, although in the case of this eco-minded horror oddity, it was American distributors who attempted to connect it to the moderately successful Troll of four years earlier.

Originally known as Goblin (no trolls appear in the film, nor are they ever referenced), the complete disconnect between title and content is but one of many baffling qualities that elevated the film to cult status, earning it a place alongside other tried-and-true – some might say “tired” – classics of the “so-bad-it’s-good variety”, such as The Room and Plan 9 from Outer Space.

Titanic II (2010)

Asylum Studios’ entire modus operandi is to produce bald-faced knock-offs of recent and/or upcoming blockbusters as fast as possible, for as little money as possible (some of their titles include Transmorphers and AVH: Alien v Hunter), so it should come as no surprise that they’d just outright call their Titanic rip off Titanic II.

A new luxury cruise liner, christened, obviously, Titanic II, sets sail along the same path as the first, only to be met with catastrophe when a massive tsunami sends a giant iceberg hurtling … well, you get the gist. What follows is a by-the-numbers rip off of James Cameron’s mega-melodrama, with less than half the run time and action entirely supplanting the romance. Viewers who consider the Birdemic movies high entertainment might get some ironic pleasure from this but others should probably avoid.

Showgirls 2: Pennies from Heaven (2011)

Part spoof, part remake, part experimental film, this unsanctioned sequel to Paul Verhoeven’s misunderstood trash classic – from writer/director/producer/star Rena Riffel, who reprises her small role from the original – is unique among other unsanctioned sequels, as it doesn’t attempt to exploit its namesake’s brand recognition so much as engage it in meta-textual dialogue. In this regard, it’s closer to something like Gus Van Sant’s misbegotten shot-for-shot remake of Psycho than anything else on this list. Considering how insane Showgirls is to begin with, such an effort makes for a fitting tribute, but needless to say, this one is for diehard enthusiasts only.

Easy Rider: The Ride Back (2012)

Even compared to the exploitative nature of most other examples on this list, the story surrounding Easy Rider: The Ride Back leaves a particularly bad taste in the mouth. Written, produced and starring former Ohio lawyer-turned-producer Phil Pitzer, who upon discovering that the rights to any Easy Rider remake/sequel were available successfully sued original producers Bob Rafelson and Bert Schneider for them, the film serves as both a sequel and a prequel to Dennis Hopper’s seminal New Hollywood classic.

The film revolves around the family of Wyatt Williams, AKA Captain America (played by Peter Fonda in the original Easy Rider) tracing their troubled relationship over the years. (Pitzer, who bears a slight resemblance to Fonda, casts himself as one of the Williams brothers.) As obsessed with the counterculture staple as Pitzer clearly is, he doesn’t seem to respect it’s political ethos, supplanting the original’s jaundiced look at America with a heavy pro-military message, replete with out-of-nowhere references to 9/11. For as repugnant as that may sound, it follows a certain kind of baby-boomer logic: Pitzer’s unauthorized sequel isn’t so much a vanity project as it is a full-blown midlife crisis caught on film.

The Bronx Bull – AKA Raging Bull 2 (2016)

Produced in 2012, but not released until 2016, Raging Bull 2 – which covers the hardscrabble life of boxer Jake LaMotta, picking up where the last film left off, while also going further back in time to examine his early years – was forced to disassociate itself from Martin Scorsese and a Robert DeNiro’s 1980 masterpiece after being hit with a lawsuit from MGM.

LaMotta had sold his life rights to the studio in 1976, and while he retained the right to pursue a sequel, MGM reserved the right of refusal, which they swiftly enforced in this case. That didn’t stop the aged prizefighter (90 at the time, he has since passed) and producers from brazenly calling their picture Raging Bull 2 and billing it as a legitimate sequel. The legal battle that ensued lasted about as long as one of LaMotta’s later fights, with he and producers quickly ceding to MGM’s demands. The film was retitled The Bronx Bull, after another of LaMotta’s in-ring nickname and released a few years later (with William Forsythe “taking over” for DeNiro) to little fanfare.