The general rule is that the first film or a season of a TV show is always the best. The subsequent movies or seasons experience a drop in quality, sometimes a rapid one, sometimes a slow one. However, that's not always the case. In fact, multiple film franchises prove that sequels can be better than the first movies.
It's not easy but it's possible. While first movies have to establish the characters and the world they live in, sequels have more possibilities. They can work with the heroes, change them, let them develop. They can create new, unexpected stories. They can become crazier, edgier, funnier, more intelligent. They can introduce new locations. The options are almost endless, and some film franchises used them well.
10 MCU
Technically, MCU features multiple mini film franchises - such as Avengers films, Captain America films, Iron Man films, etc. And just sometimes, the subsequent films were better than the first one. For example, the first Captain America movie was a solid origin story. But the following ones - Captain America: The Winter Soldier (2014) and Captain America: Civil War (2016) were on an entirely different level. Many people also believe that Thor: Ragnarok (2017), the third Thor movie, was better than the first two films. It was certainly the funniest one.
9 Back To The Future
Back to the Future is an undeniable classic - and for a good reason. The three films work even thirty films after their release. The quality is mostly balanced, but one could argue the second film has even higher stakes. Marty has inadvertently changed his life in the past and now he has to fix it - by traveling into his future! It's as complicated as it sounds but also highly funny. The third film then chooses an entirely different approach and sees the heroes take on Wild West in the 19th century.
8 Batman Trilogy
Batman Returns (2005) is an excellent start to the trilogy. But The Dark Knight (2008) and The Dark Knight Returns (2012) were a different story. The films included Batman's iconic villains without making them feel cheesy. The trilogy has a clear narrative line and sees Bruce Wayne evolve throughout the years. The ending then feels like a natural result after everything that had happened. Plus, let's not forget Heath Ledger's iconic performance as the Joker.
7 Star Trek
The first Star Trek movie with Kirk, Spock, and the original crew is a slow meditative story. The second one, Wrath of Khan (1982), is a revenge action story with an intelligent madman. And the fourth one is a brilliant time-travel comedy where Kick and Spock form an unforgettable buddy duo.
The franchise had a changing quality but most of the sequels were more audience-friendly than the first film. If it wasn't for Star Trek movies, who knows whether many other sci-fi franchises would come to be.
6 Star Wars: The Original Trilogy
No matter how many new Star Wars films might premiere, there's only one original Star Wars trilogy. Episodes IV to VI have high quality but many believe episode V is the best. Not just because of the characters but also thanks to the final twist. Everybody knows it now, everybody expects it, but it's still impressive. And episode VI finally sees Han and Leia get together for real.
5 Terminator
The new movies have very little to do with the original Terminator. However, the second film took everything awesome about the first film and made it even better. The characters were sympathetic. The effects were amazing. The film had both emotional, funny, and action scenes. Even more importantly, it showed that a villain can become a genuine hero. They just have to do it in the right way, and Terminator 2 managed it.
4 Harry Potter
The first Harry Potter movie was magical, no doubts about that. But the subsequent movies managed to do something very few franchises achieved. The audience of the same age as the heroes grew alongside them.
Harry Potter formed the taste of an entire generation, and that's something rarely any story can claim. Anybody likes a different film of the series, but Prisoner of Azkaban (2004) probably chose a most unique approach to the Harry Potter world.
3 James Bond
The first James Bond film was good. But the series only became a true hit with its following movies. Nowadays, new James Bond films belong among the most heavily-anticipated features. Once again, it depends on everybody's taste. Someone might like Sean Connery more in the role, others prefer the most recent Bond, Daniel Craig. Whatever the answer, the franchise has outdone itself multiple times over.
2 Fantomas
Let's step away from American and British franchises for a moment and focus on continental Europe. Fantomas is a French trilogy about a brilliant criminal who can change faces and usually wins over his opponent. Inspector Juve, played by Louis de Funès, desperately tries to capture Fantomas multiple times, but he makes more harm than good. The comedy-action series aged well, but there's no denying the second and third movies have a better plot structure than the first film.
1 DCEU
Finally, superheroes strike back! Just like the MCU, the DCEU isn't a typical franchise. But it does work with the same characters in multiple films. Man of Steel (2013) was a decent start but the DCEU only became truly successful thanks to films such as Aquaman (2018), Shazam! (2019) or Wonder Woman (2017). It's unclear what its future will look like, but for now, it belongs among film franchises that improved over time (albeit not always).