Hi,
Really like these human made icons, i will use them.
I was looking for a license, but i can't see one, don't you thought about using one of the creative commons for example ? (https://creativecommons.org/)
For example in France, the author rights applies, so if you don't choose a license it's very restrictive.
I'm not personally a fan of the creative commons license, as it doesn't allow the author to restrict/rescind uses for bad actors. Anyone is free to use the icons with the following 2 conditions:
1. You can not put it on products where an 'ai' art generated image is used in the final product.
2. You can not repackage or sell this icon pack to others. Credit is not necessary, but feel free to send people this way to grab an icon pack for themselves.
Creative Commons doesn't allow for these conditions I believe. But happy to be told otherwise.