The Magnetohydrodynamics equations (MHD in short) provide a macroscopic description of a plasma and provide a relevant description for fusion plasmas, the solar interior and its atmosphere, the Earth's magnetosphere and inner core, etc. However, MHD is deficient in many respect and some of these deficiencies are accounted for by extending Ohm’s law. In this talk, we take two generalized Ohm’s laws which give the Hall MHD and Lüst model. We also show how to extend the methods used to these two models to Moffatt's magnetic relaxation equations. This is based on joint work with K. Kang (Yonsei University) and J. Shin (UNIST).