Based on your query, here is how you can likely find what you're looking for:
: If "Choi Yun" is the artist, their work is most likely hosted on major art platforms. You can look for their Kill la Kill (Ryuko Matoi) summer-themed illustrations on: Download Choi Yun Ryuko Matoi Summer (Kill Kill) zip
or DeviantArt : Often used by artists to host high-quality portfolios. Based on your query, here is how you
: A primary hub for fan illustrators; search for "Choi Yun" or the Japanese equivalent. Based on your query