There was a whole thread about that topic. Local subforums are, indeed, the sub-sections where most merit points are awarded. However, I think you'll only get some there if you speak the language well (or if you engage in illegal actions like merit trading).

Altcoin subforums are the second section regarding merit points, but the merit distribution there is very concentrated on what you already found out - original postings in ICO ANNs (which may be "unofficial" parts of bounty campaigns and thus, in reality, "illegal").

The reason that other altcoin posts are not likely to be awarded is simple: There is much spam there. I tried for some weeks to merit posters in the Altcoin Discussion forum that brought up some good contents, but it was so difficult to find good posts that I got bored and gave up. I think merit sources are also not likely to search the few pearls in the amount of trash there.