Git Log: Create Patch from Selected Commit…
git.log.createPatch Write the commit selected in the Git Log as a patch, to a file or a new buffer.
How to run it
Open the command palette (M-x in the Emacs keymap) and search for Git Log: Create Patch from Selected Commit…, then press Enter. It has no default keybinding, but you can bind one in Settings → Keymaps.