Abstract: Multi-messenger astrophysics is a powerful tool for understanding the most energetic sources in the universe. Although IceCube has discovered a flux of extragalactic neutrinos, the sources of the vast majority of those neutrinos remain a mystery. We describe searches for neutrino emission from transient astrophysical source classes, both in archival searches and real-time analyses. In archival data, we use IceCube-DeepCore to search for GeV neutrinos from novae, and set the first upper limits on neutrinos from novae. We describe a planned search for neutrinos from fast radio bursts (FRBs) using the first catalog published by the CHIME/FRB Collaboration, which provides more than an order of magnitude more sources than previous IceCube FRB searches. We also describe real-time follow-up searches for neutrinos from astrophysical transients, including for the brightest gamma-ray burst ever recorded, GRB 221009A, for which we report a non-detection and set strong constraints on neutrino emission. We also describe planned follow-ups of gravitational wave events during LIGO-Virgo-KAGRA operating run 4, which is anticipated to start providing alerts as early as mid-February 2023.