Just paper again for this card, with even the butterfly being fussy cut from paper. I like the shaped top - I used a die by Wplus9 for this.
I actually made two cards using the grand piano (a Gina K stamp), but just photographed one. I feel the red check is suitably masculine, and a good contrast to the black piano. Do you see the semi-quavers on the sentiment below? That was my husband's contribution - he's playing with Zentangle patterns - he did a good job, don't you think? The other piano card was black on a wood panelling background - also a good masculine look.
This card just uses paper, and I cut out the musical instrument to layer it for a 3D effect.