Card Normals 1.0.0

Free, GPL-3.0, Blender 4.2 and later.

Installing it

1. Drag the .zip into an open Blender window, or
2. Edit ▸ Preferences ▸ Get Extensions, then the ▾ menu at the top right ▸ Install from Disk.
3. Find the panel under Item ▸ Card Normals in the 3D viewport sidebar (N).

Installed this way it is a local copy, so Blender will not offer updates for it.

Using it

Select your cards, then the surface they should borrow shading from — the scalp under hair, the canopy under leaves — and set the proxy. For grass, point along an axis instead. The blend factor mixes the result with the card's own normal, and Clear puts it back.