The anime Stella Jogakuin Koutou-ka C³-bu has just recently started airing. I asked a question about it here. The full name is too long for a tag name (stella-jogakuin-koutou-ka-c3-bu would be 33 characters). The English name for the show is "Stella Women's Academy, High School Division Class C³", which is significantly longer than the Japanese name. I haven't seen the English name used in many places.
I used c3-bu for now, but it may not be the best abbreviation. I don't know what official abbreviations exist, but it may make more sense to tag as stella-jogakuin or koutou-ka-c3-bu or some variation therein. We could also make our own abbreviation so long as search engines will catch it.