The circum-galactic medium (CGM) is at the nexus of the gas inflows and outflows that regulate galaxy evolution. Consequently, the CGM provides an ideal laboratory for studying galaxy fueling, feedback, and interactions. In the last decade, the simultaneous availability of UV spectra from the Cosmic Origins Spectrograph, deep integral field spectrographs, and wide galaxy redshift surveys have revolutionized our ability to characterize the CGM empirically. I will review recent progress enabled by the CUBS and MUSEQuBES, which combine these data for 31 intermediate redshift quasar fields, enabling studies of giant quasar nebulae in rest-frame optical emission and studies of the absorbing CGM around low-mass dwarf galaxies. These surveys demonstrate that giant CGM/IGM nebulae emitting in [O II] are common in the massive halos hosting UV luminous quasars, with morphologies and kinematics indicative of stripping, accretion, and outflows. At the same time, the deep and wide galaxy redshift surveys enable the identification of intermediate redshift isolated dwarf galaxies with CGM/iGM probed by the background quasar sightlines. At these redshifts, the UV quasar spectra enable the first constraints on the physical conditions, metalicities, and relative abundances of C, N, and O in dwarf halos for unique insights into stellar feedback models.