Mar 4, 2015
Designed by Seb Jachec and CJ Melegrito, Glacier is a system replacement icon set designed for Yosemite:
Bringing together the clean simplicity of Yosemite and the delightful details of OS X versions past, these icons are a testament to the styles of new and old.
Glacier isn't a radical departure, it's a fine-tuning of Apple's current iconography, and it's very subtle and very successful. The set is free, and for a mere $5 you can download Sketch files for every icon which is a steal. I've been using these icons system-wide and I especially love the folders and tweaked Finder icon.
To customize your system with these icons, Useful Mac recommends using LiteIcon.