

Most of those artsy keycaps that I’ve seen go do their blingy design and then encase the whole thing in clear plastic shaped like a regular key so that it doesn’t have a weird shape.
Example:
https://www.keychron.com/collections/artisan-keycaps/products/magic-animal-resin-artisan-keycap


















https://www.etsy.com/listing/1036438779/gold-greenman-14k-solid-gold-with?show_sold_out_detail=1&ref=nla_listing_details