Tiny buttons that are the right size for embellishing hearts are hard to find! I've done the legwork for you and offer Tiny (about 6mm wide) and Micro Mini (about 4mm wide) versions in a few different colours and shapes.
These buttons fit well on hearts cut from any of the 1000 Hearts templates, including the smallest layer on the embellished hearts. These are the buttons I use when making embellished and layered hearts.
The mixed packs come with 40 per pack and are hand-packaged in specific colour ranges, while the Dress It Up (DIU) packs come prepackaged as shown, with various colours, designs and quantities. Please check the photo of the pack you are selecting to make sure you are getting the ones you want (though they are all pretty gorgeous!)