Tyranitar

If you have a lot of candy - you could evolve that 26 level Larvitar and then power it up to 30 level.

If I were you I would also power up that 15/12/15 Tyranitar to level 30.

Considering that those with 13 attack have other stats at 15 I would keep them for the future. If moves will get updated and Tyranitar will still be useful - having other movesets than Bite/Stone Edge/Crunch can bring some versatility or extra power.

How many candies do you have? I’d go with the TTar to save candies and then raid to get another one, and power it up to fill out your Mew2 team. Evolving a larvitar costs a lot of candies. I’d only do that if it was a 98 or 100.