You're very welcome, and thanks for the thanks! :P
To answer your question: it's simply because I currently have over 1,000 of these portrait-format images from running a fantasy art site. I'll be uploading them all bit by bit, but I’m happy to keep your preferred formats in mind when I craft new ones in the future.
Right now, I’m still working on my bundle pack, scaling everything down through all the sizes: 128, 64, 32, 16, and 8 pixels.
https://itch.io/s/167002/-rpg-mega-pixel-art-bundle-109k-fantasy-assets
Once that's done, I’m definitely open to new projects and will keep your suggestions in the back of my mind!