Baby names websites are useful tools as well as dangerous traps. There are dozens, if not hundred of them, and when it comes to non-european/northern american names they are often full of inaccuracies — some may even be offensive. From what I read it’s especially true for South-East Asian names (Japanese, Chinese…) and Native American names. I recommend checking specialized websites for names from specific ethnicities, as using inaccurate names might perpetuate stereotypes, and otherwise just making your character unbelievable if they are supposed to belong to a particular ethnic group.
That said, they can be helpful, especially in fantasy writing. They often allow you to search names by origins, so if you have a name that you want to have in your story you can search a website to get names with a similar feeling, that won’t make your characters’ names clash.
Behind the name is often said to be a good resources, and for several reasons. My favorite feature of theirs is their ranking of most popular names per country, the information being “typically compiled by a national statistics agency, though in some cases it comes from another source”. You can also check the message boards where you’ll find name enthusiasts of all backgrounds and not just expecting parents as is often the case on traditional baby names websites. They also have a very nice references page.
As a traditional baby names website, I tend to go towards Babynamespedia which has all the information these websites use, has a feature that allows you to select a random name from the website, and shows you a diagram of the links between the name you’re looking at and its derivative.
Think baby names has a very unique feature which I recommend for creating new names: the “creative forms”. Under the list of related names you’ll find two buttons to generate either male or female names derivated from the original name, by blending them with other names. You select the ones you like, click the button again and the ones you didn’t like will get replaced, which allows you to get a nice list of names. For example, creative female forms for “Kassia” gave me Kasadia, Kinsia, Kasris, Sansia, Masia… as for male forms I got Kasnez, Kasker, Kasvil…
From what I’ve heard, Namesite.com is — despite its surprising name — a pretty accurate resources for African names of various origins.
Issendai‘s page on Japanese names is the most accurate list of resources I’ve found, and they indicate the ones that are readable online. Please don’t trust any “translate your name into Japanese” website, you can’t translate your name if it doesn’t mean anything in your language. As far as I know, the misconception comes from the fact that Japanese people use kanjis for their name and most kanjis have a meaning by itself when isolated (and different meanings according to the what they’re paired with, when they’re not isolated…), so the names do have a clear meaning.
Still with the Japanese given names resources, that page on languagerealm gives general guidelines on how to recognize if a name belongs to a man or a woman, but as with everything be careful. You can also refer to that wiktionary appendix which even gives you the name’s kanjis.