Best Arena Team (F2P)

Hi,
There is no such thing as an undefeatable team, all teams have their nemesis. Despite that, several teams are probably able to keep you in top20, with the two most commonly used at the moment being Rex (l) + zDN + GK + Chaze or zQGJ (l) + zYoda + JKA + GK + DN, Ahsoka, Aayla or Ezra. I'm currently using Rex (l) + zDN + STH + zKylo + B2 and I'm able to reach rank 1, although I will drop to rank 30 during offline period. Check this website for a report on current meta https://swgoh.gg/meta-report/.
Mike, the defensive team ai uses when you're attacked is the last team you have used in arena.