Like the above said, clans dont work like that. If you only want the clan for the tag just to boost your reputation, your reputation will most likely drop.
If you want a clan you should search for it yourself, I dont realy like the idea to recommend a clan, you just have to search for it to see which one you like the most by researching about it.
But if you want a clan just for the tag and for reputation, well good luck, you'll never find one, and if you will, I doubt they will let you stay amongst them for a while, they'll just kick you out if you weren't active or social with them.