Aria2

Aria2 is a downloads utility that's surprisingly lightweight and fast. It's compatible with HTTP, FTP, BitTorrent, and metalinks, and also supports simultaneous downloads from different servers, as well as resuming paused downloads.

The only downside is its interface, since it has to be used with the command line, which can push some users away. Still, you don't need to learn much, you just have to copy and paste the URL and the name of the app in order to start downloading.

By using other commands you can, for example, download a file from different hosts, or even speed up the downloads. Since it's open-source, there are many ways to customize it, which you can check out in the creator's official wiki.

Despite not being too pleasant on the eyes, it barely takes resources, and it's very trustworthy and portable; this makes the application a very good option to consider.