JDownloader is a free, open source download manager. It simplifies and improves the process of downloading files from Websites, Cloud-Storage Providers, Social Media Networks and File Hosting Sites. JDownloader offers downloading in multiple parallel streams, throttling, resuming, CAPTCHA recognition, and automatic file extraction. It supports Click'n'Load and container files like DLC, RSDF and CCF.
The installer contains bundled adware. Be careful during the installation: https://alternativeto.net/discussions/applications/11718/be-careful-in-the-installation/
- jDownloader is also capable of NZB downloads via plugins already included in the default setup.