A common trope with aliens is that they don't come in peace. In entertainment, extraterrestrials usually want to rule the Earth or destroy it. Many anime properties fall into this trope. As a result, alien villains permeate the Japanese animation landscape.
On the other hand, some anime works resist that urge. They introduce otherworldly beings who don't seek out conflict. In fact, most of them just want to be left alone, but circumstances draw them into danger. Sometimes, writers use this scenario for comedy. Other times, it's meant to make the real villains more despicable. Regardless of the specifics, these aliens really do come in peace.
7 Space Dandy
One of Dandy's constant companions is a catlike creature named Meow. Despite his feline appearance, he's actually an alien from Betelgeuse. Viewers don't learn much about this planet's residents. One can assume from Meow's diminutive character that his species isn't exactly warlike. That certainly tracks with what little descriptions fans get.
Betelgeuse's significance seems to come from economic stimulation. It's the largest consumer of dried fish flakes. In addition, its most popular locale is a market store. These aspects may not be anything spectacular, but that's better than standing out for the wrong reasons.
6 Dragon Ball
These big green men don't make the best first impression. The Namekians initially come in the form of Demon King Piccolo, who emerges as a devilish dictator in the original Dragon Ball. When Dragon Ball Z reveals that he and his offspring are really refugees from Planet Namek, fans are in for a shock. Not only does the evil overlord have extraterrestrial roots, but his devious demeanor is an exception to the rule.
The Namekians epitomize humble benevolence. They live in quaint villages, connected to nature through their plantlike biology and agricultural exploits. They prize peace above all, and they perceptively recognize that quality in others. This is why they happily aid the heroes and oppose the villains. The Dragon Ball franchise has seen plenty of other aliens, but none are as iconic or accommodating as the Namekians.
5 To Love Ru
Talk about being a lover, not a fighter. The Deviluke denizens may not be warlike, but they do have arranged marriages. This fuels Princess Lala's flight to Earth. She runs away to avoid forced matrimony, creating a facade of romance with a human, Rito Yuki, to get out of it. However, this has an unforeseen consequence.
Namely, Lala really falls in love with him through miscommunication. She then makes that known with her infectious enthusiasm. Rito may have eyes for another, but Lala's naïveté and positivity are hard to resist. Aliens truly don't get more peaceful than her, potential diplomatic incident aside.
4 Haiyore! Nyaruko-San
This anime has numerous alien species dedicated to peace. So plentiful are they that they've formed the Space Defense Agency. This congregation sends operatives to carry out noble missions across the galaxy.
One of these agents is Nyaruko of the Nyarlathotep planet. Upon reaching Earth, her goal is to protect Mahiro Yasaka. She has a wide assortment of weapons and armor, making her a force to be reckoned with, but she uses these tools strictly for defense. Offense is usually off the table. Considering how adept Nyaruko is at the former, Yaska couldn't be in safer hands.
3 Sonic X
Another plant-based alien prioritizes peace. Cosmo is the last of a race wiped out by the malevolent Matarex. When Sonic and friends take to space in this anime, the little survivor aids them in thwarting the cyborg menace. The only conflict from Cosmos is unintentional.
Unbeknownst to everyone, a device in her brain allows the Metarex to see everything she does. She's an unwitting tool for a nefarious purpose. Rather than play the spy, though, she attempts to flee so as not to jeopardize her allies. This selflessness goes further in the end. The climax sees Cosmos sacrifice herself to stop the cybernetic antagonists. Of all the cutesy companions Sonic has met, this alien is among the most altruistic.
2 Cute High Earth Defense Club LOVE
Not many people would suspect a wombat of wrongdoing, and fewer still would expect it to be a mighty defender. Sure enough, that's exactly what this extraterrestrial marsupial strives to be. Wombat sees the malice of the Earth Conquest Club, conjuring all manner of monsters to wreak havoc on Earth. Thus, he aims to stop this barbaric band by assembling his own club.
To accomplish that mission, Wombat imbues five kids with powers based on nature. Together, they form the titular Earth Defense Club, protecting the populace from would-be conquerors. If their intentions aren't already clear, they literally fight evil with the power of love.
1 Di Gi Charat
Dejiko comes to Earth with a purpose, but it's not to invade. Instead, she dreams of becoming a pop star. Viewers can probably guess her personality from that. She's not evil; she's just self-absorbed. She routinely teases others, oblivious to their problems. Granted, later iterations paint her as more helpful. The only time this harmless exterior cracks is when she loses her temper.
The extraterrestrial gets extra angry. Dejiko breaks out her laser eyes and other bizarre powers in fits of rage. As frightening as these moments can be, she never intends any serious damage. These episodes are akin to childish tantrums. Just like those tantrums, they soon pass. After that, Dejiko goes right back to singing. As a result, it's tough to stay mad at her.