Windows 10 has new pin icons in the Jump List. Black and white for different themes.
Old Windows 7 pin icons stayed inside imageres.dll, ID 5100, 5101.
Where are new icons stored? How get they with WinAPI?
Icons have traditionally been raster images. The benefit of raster images is, that they are blazingly fast to render. That speed comes with a downside, namely that raster images only look good at a narrow range of pixel densities. That was great for as long as most displays had a pixel density of 96 PPI (pixels per inch). With pixel densities increasing, raster images stopped being as useful as they used to be. On high-density displays, icons would either render too small, or had to be scaled up with all sorts of visual artifacts.
To address this, Windows 8 introduced font-based icons as the Windows UI Symbol font, that was superseded in Windows 10 by the Segoe MDL2 Assets font. Fonts are vector-based, and can be scaled across a wide range without (or very little) visual artifacts.
While I have not verified, whether the Windows Shell actually does use font icons, the icons you are looking for are available in the Segoe MDL2 Assets font with Unicode code points in the private use area: