I was able to find some graphics from Super Mario UniMaker that were meant for Super Mario 4 Jugadores. So I request that someone can port the Mario graphics below to SMBX.
mario-1: https://postimg.cc/gallery/mCg0m3f
mario-2: https://postimg.cc/gallery/8fcpKTz
mario-3: https://postimg.cc/gallery/13SyPqQ
mario-4: https://postimg.cc/gallery/b8qBWP7
mario-5: https://postimg.cc/gallery/B4tWXsQ
mario-6: https://postimg.cc/gallery/XbLTcpG
mario-7: https://postimg.cc/gallery/JmXMRZK
mario-9: https://postimg.cc/gallery/F1FXq11
mario-10: https://postimg.cc/gallery/cshxpn7
mario-12: https://postimg.cc/gallery/ZWqkR51
For all of these images, Mario is facing right. For Mario to face left, just flip the sprite.
I couldn't find Frog Mario, Mini Mario, or Mega Mario.
No Luigi sprites unfortunately
Original graphics made by Neoweegee