It was already mentioned but Bokura no Kiseki fits the bill, since the whole premise of the story is about characters from another world being reincarnated on this world. Not many chapters are out, but they are lengthly so they should last you a while.

Another story that comes to mind is a one-shoot Toukyou Hatsu Isekai Yuki, The first one is about just that.

Another story that was already mentioned is Shut Hell, with is about a Japanese guy that is the reincarnation of a Chinese outlaw? from the past that fought against the Mongol forces.

Thanks for all these awesome posts!

I read Bokura no Kiseki and, though admittedly it was sort of the opposite of what I was looking for (reincarnates into the present world, not another world), it was closest to what I requested! Plus I love the characters, which is always a bonus ^^ thanks to the two users who recommended it!

All the other series, consider them to have been tried, read, or already read. No Game No Life was pretty good (but short haha), and so was Re:Monster. Thanks also to the user who PMed me some Korean titles: I'd actually read half of them but the other half I'll see if I can get a hold of.

Thanks again everyone!

I believe that the best mangas are still out there, waiting to be discovered.

Theres one about a guy thats reincarnated as a maou i think cant find the manga tho. And theres one about this guy thats reincarnated as the WEAKEST... but im looking and cant find... i will come back later

kyo kara maoh! ?
i may be wrong though...

Fujoshis rule!

You would probably like these then

Desolate Era
Douluo Dalu
Re:Monster
Mushoku Tensei - Isekai Ittara Honki Dasu
Eh? Heibon desu yo??

Since all of them are about reincarnating to another world and starting off at a young age (reborn).