Tread Lightly
Tread Lightly gives every block its own footsteps. Vanilla picks one sound per block and plays it at a fixed rate. Tread Lightly works out what is actually under each foot, in turn, and plays something appropriate for how you are moving over it.
It replaces the sounds, not the game. Nothing is added, nothing is craftable, no block or entity behaves differently, and no world data changes.
What a block sounds like is defined by a pack, not by the mod. Block maps, acoustics, and audio all come from resource packs, read through the ordinary resource pack system, so packs stack, reload with F3+T, and override each other in the order the player sets.
Adding a sound to a block requires no code and no mod update.
The mod runs entirely on the machine that renders the world. A dedicated server neither loads it nor needs to know it exists, and two players in the same world can run different packs and legitimately hear different things.
This is a deliberately smaller take on the idea than the mod it comes from: a leaner engine and a format meant to be legible to someone who has never seen it before.
Minecraft 1.21.1, 1.21.11, 26.1, 26.2 or 26.3, each with a recent NeoForge. The 26.1 file covers 26.1, 26.1.1 and 26.1.2. Client side only.
Tread Lightly is licensed under the GNU Lesser General Public License, version 3 or later. The full terms are in LICENSE, which incorporates COPYING by reference. In practice:
Tread Lightly began as a port of Presence Footsteps, used under the MIT licence it carried at the time. That attribution, along with trademarks and third-party licences, is in NOTICE.