I use this one: https://querytracker.net/ it's free unless you want to do some special things, then it's $25 for the year--but the lists of agents doesn't cost
anything at all to see them and their links and info and even read feedback from folks who have queried them.
Then here is the Association of Authors' Representatives: http://aaronline.org/ This is where you can verify if the agent is legit.
And while I don't really use this site, I know it to be reputable and they list info about agents and include whether they are AAR members and such.
http://www.agentquery.com/
Love and stuff,
Michy ~~Infinite Diversity in Infinite Combinations~~