Legitimate sites
As long as you don't click on the ads you'll be okay
General job search sites
Glassdoor
I love this site, and Indeed because they include employee reviews of employers.
LinkedIn Jobs
Get on LinkedIn if you are not yet, many employers will look for you there if you apply for a job.
ZipRecruiter
Take the time to enter all your information into ZipRecruiter and you will have a very easy time applying for jobs and they will send you job matches via email.
Salary.com
There are a lot of ads on this site so just be aware of what is a job listing and what is an ad. Some ads are scammers trying to get your information or try to get you to pay for their special (worthless) job listings.
Monster
Layout similar to Google. I like that they show links for common searches at the top.
Indeed
Includes employee reviews as well as the ability to compare employers with a side-by-side rundown of ratings, salaries, and more.
Career builder
Jobs.workable.com
This is actually the backdoor into recruiting software called Workable but there's a job board so, have at it, I did.
My tip: If you have a long history like I do, start with a complete, over-stuffed resume with every job and all their dates and job descriptions including hard and soft skills. That way you can start with that resume for every job and just delete what is not relevant and resave under the new job name. This will keep you from being overwhelmed at every new application.