Electromagnetic metamaterials have already proven very valuable for the enhancement and molding of RF magnetic fields within ultra-high field MRI scanners at 7T. We report on our development of coil elements based on composite right-/left-handed (CRLH) 1D electromagnetic (EM) metamaterial transmission lines (metalines) operating in the zeroth order resonance (ZOR) to foster uniform RF magnetic field distributions along the scanner axis. Tailored EM metalines supporting full-wave or quarter-wave resonances are used either as metamaterial ring antenna or as dual-band coil elements for simultaneous 1H/23Na imaging. The EM metalines are key to the MetaBore, which is a fully adaptive RF field control scheme based on a periodic axial arrangement of conformal metamaterial ring antennas in the framework of high-field traveling-wave MRI. With the 2D EM metamaterials (metasurfaces) we realized high-impedance surfaces (HIS) in order to enhance the uniformity and directivity of the RF magnetic field from e.g. overlaid (elongated) dipole elements towards the probe volume. The designs include simulation studies of the overall multichannel coil systems, which are carried out with our home-made, open source electromagnetic 3D EC-FDTD solver openEMS supporting conformal cylindrical inhomogeneous meshing. Experimental verifications of our coils have been carried out within 7T MRI scanners (Siemens Magnetom).