The decorative wood on a staircase is called "wainscot"
Applique is a decorative form of needlework where a smaller piece of cloth is sewn carefully onto a larger item. Applique patterns are available for sale or free at a variety of sites online including freeapplique.
Do you mean the piece that is between the head and the shaft? If so that is called the ferrule.
Etui
I think that would be called a "pedestal".
The cornucopia is also called the horn of plenty. It is a symbol of abundance and is often used as a decorative piece.
"Her needlework was terrible!" or "The needlework on that dress was very detailed."
The answer depends on exactly what it is that you want to find. Applique is a type of decorative needlework. It is used on many sorts of clothing, bed linens, quilts, and every other textile.
The decorative top of a column is called the capital.
The piece that screws the lamp shade onto the lamp is called a finial. It is typically a decorative knob that screws onto the lamp's harp to secure the shade in place.
The decorative curl on the end of a violin is called the scroll.
"Decorative" when describing fruit trees, means no fruit. It is called a decorative Red Plum tree.