Usually the downloader you need depends on the website you want to download the images form. In general, here are some opensource ones which support a variety of websites: gallery-dl, ripme and various other ones on github. There for paid ones, there are Extreme Picture Finder and Bulk Image Downloader, which have easier to use GUIs and are properly maintained, but as said, they are paid. Source: about 3 years ago

Yeah, I found bulkimagedownloader ages ago but its not a free tool. Not sure of what limitations the trial have. Source: about 3 years ago

I don't want to download a sieve from a russian forum. Hover Zoom+ is working fine. Source: almost 2 years ago

Hover Zoom+: https://github.com/extesy/hoverzoom/ (this is the open source one, not the old one with malware). Source: almost 2 years ago

It works in places that Imagus had stopped working. He also has a Github page for it: https://github.com/extesy/hoverzoom/. Source: about 2 years ago

It's working good for me. I know there are a few hoverzoom extensions that make it confusing: This is the one I'm using. Source: over 2 years ago