While "I'll be back" is most associated with the Terminator franchise, Arnold Schwarzenegger has also used the catchphrase in many other movies. He might not rule the box office anymore, but Schwarzenegger was no doubt one of the biggest movie stars in the world during the 1980s and 1990s. He starred in lots of big hits, and even when one of his films would flop, neither the studios or the audience would seem to hold it against The Austrian Oak.
The movie that cemented Schwarzenegger's rise to stardom was 1984's The Terminator, the original entry in James Cameron's time-traveling apocalyptic franchise. To this day, the T-800 remains Schwarzenegger's signature role, a status only increased by him becoming the hero in Terminator 2: Judgment Day. The T-800's most famous line is "I'll be back," originally said before busting into a police station holding Sarah Connor and slaughtering just about every person in the building. He said it again in Terminator 2 and Terminator Genisys, and other characters say it in Terminator Salvation and Terminator: Dark Fate, making it a trademark of the series that only Terminator 3: Rise of the Machines misses out on.
In addition to being a trademark of the Terminator franchise though, "I'll be back" followed Schwarzenegger to multiple unrelated films, and was even used in campaign speeches during his political career. Here's all the times he's said "I'll be back" onscreen, outside of the Terminator movies.
Commando (1985)
A mere year after The Terminator, Arnold Schwarzenegger starred as Commando's oddly named John Matrix, a retired special forces colonel. When a former South American dictator kidnaps John's daughter and tries to force him to assassinate the new president, he turns into a one man army and shows them why messing with his family is a really bad idea. Early on, John tells sub-villain Bennett "I'll be back," and actually gets an answer, as Bennett says "I'll be ready." Later, John helps Bennett let off a little steam, in one of Commando's best kills.
Raw Deal (1986)
The year after Commando, Raw Deal saw Arnold Schwarzenegger play former FBI agent and current small-town sheriff Mark Kaminski. Mark was forced out of the FBI after brutally beating a suspect accused of rape and murder. He's now given a chance to get back in, but off the books, and only if he can successfully infiltrate and bring down a dangerous criminal organization. Arnold slightly alters his catchphrase here, telling a bad guy "I'll be right back," but it's close enough to count. Again, this is followed later by Kaminski killing that character.
The Running Man (1987)
About a year after Raw Deal, Arnold Schwarzenegger played protagonist Ben Richards in The Running Man, a loose adaptation of Stephen King's "Richard Bachman" book of the same name. Real-life Family Feud host Richard Dawson played Damon Killian, the villainous host of the titular dystopian competition, and was delightfully slimy in the role. At one point, Richards tells Killian "I'll be back," to which Killian responds "only in a rerun." As per the pattern, Richards later kills Killian, making it clear that "I'll be back" is pretty much always a death threat.
Twins (1988)
One of the few straight-up comedies Arnold Schwarzenegger has played the lead in, Twins casts the Austrian Oak as Julius Benedict, the unlikely twin brother of Danny DeVito's Vincent. The pair was created as part of an experiment to combine DNA and create the perfect child, with Julius becoming such a person, and Vincent getting the genetic material left over. Lied to about their mother having died, Julius gets her information from the doctor who ran the experiment, saying on his way out "If you're lying to me, I'll be back". He wasn't, so Julius didn't come back to kill him this time.
Total Recall (1990)
In Total Recall, Arnold Schwarzenegger plays Douglas Quaid, a man with a boring life who signs up to have memories of a Mars vacation implanted in his mind. During the process, it's revealed that Quaid has a secret repressed life, causing things to go haywire, and sending him down a journey of excitement and danger. Or at least that's what it seems, as many fans feel everything that happens to Quaid after he starts the Rekall process is a dream. Either way, Quaid still says "I'll be back," keeping the Schwarzenegger tradition alive.
Last Action Hero (1993)
Appropriately, thanks to its meta nature, Last Action Hero celebrates "I'll be back" being Arnold Schwarzenegger's catchphrase by making fun of it. When protagonist Danny Madigan goes inside Schwarzenegger's latest movie, his in-movie character Jack Slater says the phrase twice, and Danny makes note of it being what the audience expects. Later, a villain uses it on Slater in the real world, who replies, "the hell you will." Schwarzenegger also plays himself in the film, just for added meta factor, and is of course saved by Slater.
The 6th Day (2000)
In The 6th Day, Arnold Schwarzenegger plays Adam Gibson, who's accidentally cloned as a result of a powerful conspiracy, and is then thrust into a battle to reclaim his life and defeat those who wish to silence him and keep his cloning a secret. Before all that, the Gibson family dog dies, and Adam visits a pet cloning store, but ultimately decides not to get one for the time being, finding the idea of cloning their deceased pet creepy. As he leaves the store, an unsure Adam says "I might be back," in an ever so slight variation on the "I'll be back" catchphrase.
The Expendables 2 (2012)
After making a cameo appearance in Sylvester Stallone's original action star team-up film The Expendables, Arnold Schwarzenegger returned for a bigger role in sequel The Expendables 2. During the film's final battle, Schwarzenegger's Trench Mauser tells Bruce Willis' character "I'll be back," to which Willis replies "You've been back enough. I'll be back." Schwarzenegger then responds with Willis' Die Hard catchphrase "Yippee-ki-yay," just to hammer the joke home. The Expendables movies may be lots of fun, but they're not exactly subtle.