I'm immediately drawn to anything having to do with quatrefoils. I think maybe it's the symmetry I find so interesting. I love the variation on the pattern; it can be portrayed in the simple cloverleaf shape or can become something more complex and ornate.
Found in fabric: In it's simplest form, the classic Maharam Quatrefoil fabric by Alexander Girard
Found in artwork: Classic Symmetry Aqua Print from Crate and Barrel adds a bit of metallic flair to the classic shape
Found in wallcovering: York Wallcovering's Rosato pattern features a large scale quatrefoil-shaped damask that adds a level of sophistication; image from Interior Design magazine
Found in tiles: These tile variations from Craftsman Court Ceramics include intricate levels of detail that play on the original shape