I remember the Silk icons, I still have a soft spot for them. I even tried using them in an app, but they upscale very poorly even with xBRZ (IIRC I used something like https://sourceforge.net/projects/xbrz/files/ScalerTest_1.1.z...).
Similarly, Visual Studio actually comes with an icon library at https://social.technet.microsoft.com/wiki/contents/articles/..., though 2012 sadly switched from 3D icons (a mixed bag, some beautiful ones and then some awful ones like a downscaled yellow-shaded XP-era exclamation point triangle) to flat line art indistinguishable from today's icon style except in having backgrounds. You can find "totally legal" offline downloads of VS2010 on archive.org (the online installer is down).
> I even tried using them in an app, but they upscale very poorly
Someone made the effort and ported them to .svg [1]
Donationware
Interesting icon set. I love the idea behind it, but looking at their icon preview at https://i0.wp.com/codefisher.org/wp-content/uploads/2022/08/..., I noticed that some images look great at higher resolutions (the star), while others look like a bad hqx/xbrz job, with a mix of curved, pixel-aligned (lock, book, anchor, monitor stand), and blurred features (book stripes), with inconsistent line widths (the house's roof and bushes, the computer stand and anchor).
[1]: http://famfamfam.com/lab/icons/silk/preview.php