My favorite tank in low level games with high mana is currently Shieldbreaker. A lot of health, up to 10 with the summoner Mother Khala and as I can put 2 healers in my holy deck he is near to invincible. The only way to kill him is to survive as long as the healers die in the back...

PS: I'm really sorry, that RNG is not giving out points for creativity. I think my summoner could have received some more credit there :D

And a !PIZZA for you for good measure :)