This paper presents a review of diverse superfluid pairing mechanisms and their associated manybody states in polarized Fermi gases. Based on the Bardeen-Cooper-Schrieffer theory, we analyze the role of Fermi surface properties in governing atomic pairing behavior, and subsequently introduce the finitemomentum pairing mechanism. Then we examine how spin-orbit coupling, serving as an artificial gauge field, modulates such finite-momentum pairing states. Furthermore, we focus on the the altermagnetic state, which is featured with broken time-reversal symmetry and vanished net magnetization. We discuss that its alternating polarization in the momentum space can lead to the Fermi surface anisotropy that generates unconventional pairing associated with the spatial point-group symmetry. Finally, we discuss the polaron with the quasiparticle behavior manifested by minority impurity atoms in the extreme polarization limit, and explore its applications in probing many-body physics. These above investigations reveal the rich phase diagram of polarized Fermi gases spanning from collective pairing to single-impurity excitations, and lay theoretical and experimental groundwork for the exploration of novel quantum many-body states.