When everyone on your team picks a damage dealer what do as mid?

If I'm last pick or if I've already chosen. I generally choose cassioepiea because of the whole hyper carry thing, but I dont like galio in a team of damage dealers because he can't "really" engage... He's basically the only tanky option aside from gragas whom i havent played in like 4 years. What do? Yes this is freaking bronze i hate it too, noone above silver would build a team consisting of teemo,vayne,riven (probably going to be toxic or feed), kaisa jg, and fill in the blank.