Of course it is possible. Countless of national teams have been released already, and if you want to collect them, I think you have to put some effort into it. Start collecting and building on your own, and only once you have less missing teams than not - ask for additional teams.
It would just be too much to ask for someone else to do this for you.
And also -BEFORE you release - it's a good to idea ask whomever is your sources. Some people (like myself) don't care as long as we are credited, but others might be more sensitive. Save the names of your sources so you can include them in the credits.
You might want to learn how to transfer & edit teams from earlier FIFA-s to 16 & (with patch owners permissions naturally) do that, as well as update it. I know Robbie_DL is making UEFA euro 2016 patch where (at least as i understood) he might add some teams outside of UEFA area too, so 1 area is already covered. Im sure he would accept the help if you can give it (personally i would help, but just putting it plainly- i simply have no time)
yes, the thing is older fifa has great patches like road to world cup 2014 with more than 200 teams.
so actually i just have the uefa from robbie
the copa patch with conmebol and concacaf is down
afc and caf or ofc i tried to search but i didn't find anything
how can i import teams from older fifa in fifa 16 ? with creation master doesn't work, isn't it ???