For me it was a close call between the Kraken and the Dire Wolf.
The Kraken is plausible, but unlikely. We have known for decades that giant squids exist, and we did just catch one on video and alive. When talking about the Kraken, however, we are talking about something much larger. Now we have mapped the moon, but we have only explored and mapped about 5% of the ocean floor. It is possible for something that massive to live that deep in the water. At that depth the pressure is so great that the body make up of animals would either be made of liquid, or be extremely large to balance out the pressure.
The Dire Wolf here is the most likely to be found. The Dire Wolf is the only creature on this list that is a confirmed extinct species. It went extinct around 10,000 years ago. Animals that have gone extinct have been popping up here and there lately. I would be possible for the Dire Wolf to come around as well.
I would agree with Big foot, but He is just too unlikely. If it exists, we don't know what it is. It could be an extinct ape, or a new species all together. That doesn't make him all the less likely though. What kills it for me is the over whelming contradictions in the evidence. Plaster feet of different shapes, sizes, number of toes, shape of toes. Different types, lengths, colors, consistency of hair. The evidence, as much as there is, just doesn't add up to each other.