Best defensive teams for grand arena?

Before the major revamp of grand arena including crystals I rarely bothered to really get involved in this holotable due to the lackluster rewards. I would simply put my best teams on defense and leave it at that. Now that participating is a little more important I actually have to spare enough squads for attack as well as defense resulting in me utilizing slightly weaker squads to fill the gaps. What are some of the better defensive teams I should invest in?