If you are looking to generate these "digital paper" proxies for a project, follow these standard steps:
Use software like Adobe Premiere Pro or DaVinci Resolve to "transcode" your raw files into a more manageable format, like ProRes Proxy or DNxHR. FILMY PROXY
Using tools like MTG Print to generate high-quality card images. If you are looking to generate these "digital
Printing on thin paper or sticker sheets and sliding them into a card sleeve in front of a real card for proper weight and feel. How To Make FOIL Proxies For Magic: the Gathering FILMY PROXY