Please note the current set available here (currently Version 3.2) is copyrighted but can be used without cost under the terms of the LGPL 3.0 open source license referenced in the required attrition text.
If you are looking to monetize these vectors via sale of NFTs (or any derivative of these vectors) please note:
These vector files (or derivatives of them) may not be be used in any way to create NFTs (Non Fungible Tokens) for sale, sharing or any other purpose commercial or otherwise. NFTs are not compatible with the LGPL 3.0 license.
Per the license, it is required to provide the standardized attribution text in a publicly visible fashion, either as part of your product or on a publicly accessible webpage.
Vectorized Playing Cards 3.2
Copyright 2011,2021 – Chris Aguilar – firstname.lastname@example.org
Licensed under: LGPL 3.0 – https://www.gnu.org/licenses/lgpl-3.0.html
More information can be found via the FAQ (Frequently Asked Questions Page)