Tropes are often treated as something to avoid, but I like to think that tropes can be well done. Sure, some tropes have harmful stereotypes or are far too overdone, but below are a few tropes that I like to see. There may be spoilers ahead for some fantasy and sci-fi series, movies, or books, so proceed with caution!
1. A character having a disability that turns out to be a superpower
Whether it's artificial limbs or a blind person with extra senses, this trope always cheers me up. As a disabled woman, I don't always see myself reflected in the media. One of my favorite examples of this trope is Deadpool. Deadpool has cancer throughout his body, regenerating his cells and making him immortal. Another great example is Geordi from Star Trek: The Next Generation's ability to see details other characters can't with the use of his visor even though he's blind.
2. A historical or popular figure mentioned in a different context
Occasionally, a story will mention a famous person in a different light based on the story. A humorous example of this is in Men in Black when Kay explains that Elvis was an alien visiting Earth.
Elvis is not dead. He just went home.
A more serious example is Dan Brown's The DaVinci Code when the plot attributes purposes to DaVinci's artwork that the artist probably didn't have.
3. Humans are descended from aliens
A common sci-fi plot twist is that humans are actually descended from aliens. This has been used in television series like Star Gate, Battlestar Galactica, and Star Trek, as well as the movie Prometheus. It's a great way to explain why humans look just like another alien species, allowing actors to use less make-up and prosthetics. It's also just fun to think about.
4. Alliance between worlds
In Star Trek, the federation is an alliance between several intelligent species from different places in the galaxy, not unlike the United Nations. A similar alliance is central to Babylon 5. It's a beautiful sentiment that even other species so unlike us would be able to communicate with us well enough for diplomatic relations.
5. Prejudice against magic
This is a trope that I first encountered in the Harry Potter series. In Harry Potter, muggles who are aware of magic often look down on it as unnatural and wrong. This helps set the world of magic apart from the mundane world and gives a reason for wizards to be in hiding. In the BBC series Merlin, magic is illegal, and practitioners of magic are put to death. This creates obstacles for the titular character, who is learning to use his magic.
6. Fantastic changes to mundane laws
The most recent and notable example of this is Captain America: Civil War, in which the plot revolves around the need to hold superheroes responsible for their actions. There is a rift between the heroes as to whether there should be laws regarding their use of force. A similar problem is mentioned in My Hero Academia, where 80% of the population has developed quirks (i.e. superpowers), and laws have had to adapt.
7. Unclear or vague prophecies
This is another trope used in the Harry Potter series. There is a prophecy that Voldemort only hears half of, causing him to try to kill Harry, which seals his fate. Likewise, in Good Omens, there is a book of helpful but vague prophecies that are difficult to understand out of context. Unclear prophesies are a great way for a creator to foreshadow certain events without giving away the ending.