WallPaint

WallPaint lets you recolor any block's face with a brush - no block is placed and no space is taken. The paint hugs the surface, follows the block's shape (stairs, slabs…), and is saved into your world.

Single-player focused. Requires Fabric Loader and Fabric API.  For multiplayer, install it on both the Fabric server and the clients (required on both sides).

Tools:
• Paintbrush - right-click paints a face, left-click erases. Never breaks blocks.
• Texture Paintbrush - the paint takes on the block's own texture (tinted).
• Paint Bucket & Texture Paint Bucket - fill a whole connected same-block surface in one click; left-click clears a same-colored (50x50) area.
• Pipettes - click a painted face and the pipette becomes that exact tool, already colored.
• Whole-block coat - hold a paint bucket in your off-hand and a brush in your main hand: right-click coats all six faces of the block at once (color and style from the brush), left-click clears it. Handy for fences/balconies and other blocks with thin, hard-to-reach parts.

Colors: dye the tools like leather armor (any dye, mixable). Undyed - white.

For Minecraft 26.1.2. (MIT).