Topological nodal lines in metals, featured by a closed loop of the inverted bands in its bulk phase, result in the nearly flat drumhead-like surface states with a unusually high electronic density near the Fermi level. In this report, we will discuss several pure metals hosting these special topological nodal lines in their bulk electronic structures. In particular, beryllium is a simple alkali earth metal, but has been the target of intensive studies for decades because of its unusual electron behaviors at surfaces. We discover that in Be harbors the Dirac nodal line that in turn helps to rationalize many of the existing puzzles (i) severe deviations from the description of the nearly free electron picture, (ii) anomalously large electron-phonon coupling effect, and (iii) giant Friedel oscillations. In addition, we will discuss their potential applications of these lines in metals.