Ehy everyone, thank for your kind answers and advices! So YDVitamins, I found the website: it was Lospec, the palette is the Endesga 32, this one:
https://lospec.com/palette-list/endesga-32 This palette was made by Endesga and not by me, I liked it and wanted to do something with it. Sorry If I seemed like the worst beginner ever with my answer.
Now, well, for the issues about the colors, I've used those because I wanted something dark, so I worked with the colors that I had that I thought were the best for him. To be completely honest I'm not that happy about his a green for his clothes, but I can't make everything dark blue, and we all know that. This is just something that I wanted to do to represent my character while we play, something that usually is done with miniatures, probably I'll scale him up to a 128 x 128 or more and print it to use it while we play, so animations are not a problem at all, I'll never use it for anything more than that. I think with just a green "shirt" it would be empty.. Sorry if I wasted your time not posting everything that I should've posted previously, I should've made myself clear from the start. Sorry again and thanks a lot for the help you're all giving me.