From my research a few years ago, there were basically two major options JDownloader and Internet Download Manager (IDM). I used JDownloader for a few years and honestly loved it, it was quick and easy to use. However, when I got a virus, I was told that JDownloader "opens the door" to your computer for malware and viruses. The old adage that nothing is ever free applies here. Since then I purchased IDM, used it for a few weeks in free mode and ended up purchasing it. It is a far more complicated program than JDownloader and has options that I don't even use, but for basic downloading it works pretty well.
So there is my two cents...keep in mind, I did this research a few years ago and things may have changed with JDownloader and there might be other options available now. Let me know if you have any questions!