Clive Cussler has several long running series, some of which are done with other authors co-writing. There's the Dirk Pitt adventures with 22 books currently, The NUMA files with Kurt Austin currently at 11 books, The Oregon Files, currently at 9 books, the Isaac Bell adventures, currently at 6 books, and the Fargo Adventures currently at 4 books. He's also done some non-fiction books and even a pair of childrens books.
My personal favorites are the Dirk Pitt books, I started reading them as a teenager and remember well when "Raise the Titanic" was made into a movie. While the movie itself bombed, the score from that movie is a favorite of mine and there are many memorable scenes that have stuck in my head. Additionally, "Sahara" was turned into a movie that was relatively popular and I enjoyed it myself.
A lot of the other series exist in the same universe and it's not unusual for crossovers to occur. The Isaac Bell adventures take place in the early 20th century, but the others occur during modern times. I've enjoyed the Isaac Bell books and the Oregon files books, but the others that I've read haven't caught my attention as well. I've read his non-fiction books and found them interesting as well.