Where would DevOps Engineers mostly look for their next opportunity and what would it be?
Understand that the term DevOps refers to both a Strategies and Tactics.
For instance, the strategies of Continuous deployment and Consistent development/production environment.
The tactics may be using Kubernetics for deployment to the cluster with Docker for development/production environment.
With that said, a DevOps shop will likely use Kubernetics and Docker as their tactical tools and would look for people with those skillsets.

ALSO, they would look for people who are a CULTURAL fit who would work well in a collaborative environment.  If your background is let's say operational and your not open to learning programming skills(or learn what the programmers need), don't take ownership of a project or work well in a team...you will NOT be a fit for the company (you won't get hired).

As far as the best place to find a DevOps related job?

I would look at going to a DevOps Meetup, go to trainings/seminars where DevOps tactics and tools are taught (i.e. Docker, Vagrant, Ansible, Kubernetics, etc.), look for certain keywords in the posts such as SRE (Site Reliability Engineer), Systems Automation, etc... and do some research on companies that are moving to or have embraced DevOps Strategy.

If you understand these things, I believe it will give you a great advantage at landing a job in one of those companies.