Having a unique name can be a blessing or a curse depending on what the name is. Names follow people their entire lives and can affect how others view them. Some parents play it safe and name their children something classic like Ashley or Tyler, and this isn't exclusive to the West. Japanese parents also try to give their children names that are unique, but which still fit within societal expectations. However, this rule does not apply to anime, where characters are often given names that are puns or based on what abilities they have, such as the casts of My Hero Academia and Sailor Moon.
Japanese names are usually made up of kanji, which is one of three writing systems used to make up the language. Kanji can be combined to create more complex words and names. In Europe, family names were usually based on occupations or whose son was whose -- Johnson, Wilson, Weaver, etc. Japanese names were usually based on where a person lived or what clan they belonged to. Many Japanese family names come from nature and places found in Japan, such as Yamanaka (the middle of the mountain) or Kawaguchi (the river's mouth).
Anime and manga allow this idea to be taken to an extreme, but realistically, many names found in anime wouldn't be used in everyday life. Sailor Moon's Tsukino Usagi is an example of this. Her name is a pun on the legend that there's a rabbit that lives on the moon making mochi, with 月 tsuki being "moon", 野 no meaning "field, civilian" and うさぎ meaning "rabbit." Put together, the name could be translated as "moon civilian rabbit." The pun comes from the sound the full name makes when said all0together. No の is a possessive particle in Japanese, so the name sounds like Tsuki-no-Usagi -- "the rabbit of the moon."
While there are certainly people with the name Usagi, it's not something that one would normally name their child. Another example of a name that sounds legitimate but is actually not realistic is Kurashita Tsukimi from Princess Jellyfish. Tsukimi 月海 is made up of the kanji for moon and ocean but is considered a "kirakira name." Kirakira names are those that are not only unusual but use pronunciations of kanji that most people would not use or don't use at all. They're the Japanese equivalent of giving special spellings of common names in the West, such as spelling Caitlyn as Keightlynn. Kirakira is an onomatopoeia meaning "glittering" or "shining." Numerous anime names fall into this category, as they can be considered weird or uncommon.
Some of the most infamous kirakira names involve Pokemon. One child was named Pikachu 光宙, with the kanji for light and space being used. Another was named Mewtwo, written as 弥有ニ. Some names have even been legally banned after parents tried naming their children using them, one of which was Akuma, which roughly translates as "devil." Legislation against these names has increased over the years.
While it's safe to assume that names like Vegeta and Luffy aren't common or everyday Japanese names, some series set in more realistic settings make it difficult to determine if a character's name is a usual Japanese name or one that the creator made up. For the most part, the majority of names found in anime and manga are not used as actual names, although there are some exceptions. There will always be parents who try to name their children something special to make them stand out, no matter where in the world they are.