In order of appearance:

• Vent Wall
• White Latex Block
• Infuser
• Purifier
• Dark Latex Block
• Box Pile
• Vent Hatch
• Retinal Scanner
• Laser Emitter
• Lab Table
• Cardboard Box
• Iron Crate
• Lab Door
• Blue Lab Door
• Computer
• IV Rack
• Speaker
• Vent Fan
• Wolf Gas Canister
• Canned Peaches
• Latex Puddles (if you can walk on it long enough to hear it...)

Relevant Video:

After looking into this issue, it appears to be from Presence Footsteps being an over-engineered mod, and requiring mod developers to create their own block -> sound map, instead of determining sounds by block type. However, I will look into creating a block -> sound map for the Changed mod.

Alright cool, no more (mostly) silent footsteps. Thanks! :D

Actually, something just came to my mind @LtxProgrammer
Presence Footsteps has a option to change the "stance" from 2 legs to 4 legs. Making the footsteps sound as if you had 4 legs, obviously.

Unsure how easy or if possible, but this option could be perhaps changed by the mod whenever you become the fused knight transfer to 4 legs (because... you have 4 legs.)

I'll look into that.

Done. Need to possibly implement custom processor, for slithering.