Like the concrete heart: DrCraze
Like the silver heart: SLR Adornments
FYF (For Your Fashion): You can find these necklaces on Etsy. Etsy is a website where buyers can purchase unique jewelry, clothes, homegoods, etc. from designers all over the world. Artists and sellers, you can sell your products on Etsy also! Their website says it best: "Our mission is to enable people to make a living making things, and to reconnect makers with buyers." Genius.