Revival's Underfell has an update again after taking a one-month hiatus due to the lead dev Badger getting married, but after settling down a bit, is said to be making steady progress with new sprites, music, and art, as well as cleaning up old code and rewriting parts of the script.
https://gamejolt.com/p/july-2025-we-re-looking-for-new-members-idxiytcr
Devs are also looking for pixel artists to supplement their existing ones to help lighten their burden, so if you like Underfell and can do pixel art, maybe consider lending them a hand through this link: https://docs.google.com/forms/d/e/1FAIpQLSft2o9Ok_J9O44DJ7zX_ov3NZ-UTfXfQZL2dTgcEQWjZMZTdQ/viewform?usp=dialog or message them on their Discord server: https://discord.gg/BhWadaWbBa