I'm 16 and i speak 6 languages, what other languages would be easy for me based on these?

German, Norwegian, Danish, Italian or Romanian would be rather easy for you to learn. Russian would be rather hard, as far as the grammar, because Russian is a very highly inflected language (meaning that the grammatical function of words is specified by the word endings rather than by the word order in the sentence). It can be very difficult to speak more than the most basic Russian if you dont get the grammar right. Small grammar mistakes can make even simple Russian sentences unintelligible. German is also an inflected language, but the grammar is quite a bit simpler than Russian. None of the other languages that you speak are inflected. Japanese, although it is entirely unrelated to any other language you speak (at least Russian in an Indo-European language), might be easier for you to learn, since it is also an uninflected language. The main drawback to Japanese is the writing system, which is very complicated and hard to learn, but the spoken language is not that difficult.

These are all Indo-European languages, so other Romance languages (Italian, Romanian, ...) and Germanic languages (Afrikaans, Danish, Dutch, Norwegian, Swedish, ...) would be easy. German is a bit harder as it has a fully-inflected grammar.

Russian would be relatively easy, being also a Indo-European language, but a bit harder than German. The same with Hindi/Urdu and Persian.

But Japanese is a language isolate, and much harder than Russian, even harder than Arabic, Chinese or Korean.

Quoi ? 6 langues ? Anyway, it's hard to say which one would be harder, both have different alphabets. The Russian alphabet is the most similar to the alphabets you'd be familiar with, while Japanese grammer is probably simpler. A Russian word would look something like; русский, while Japanese letters are; 最後. I'd recommend you look over some basic grammer in both languages, though having a language more outside of Europe would be a good change

Italian, Danish, German, Norwegian, Romanian, Faroese, Dutch, Afrikaans, Esperanto, and maybe Icelandic.

De donde eres? Eres de Europa? Sabes hablar en Gallego? O Euskara?

Learn Occitan, it is very similar to Catalan

-Norwegian

-Danish (perhaps)

-Italian

-Occitan