As the science goals of accelerator-based scientists become more ambitious, the accelerator community has been pushed to both advance existing technology and introduce new tools to meet the demand. In the field of radio frequency resonators, this has mostly meant significant work to improve reliability, performance, and cost of high-gradient resonators for the International Linear Collider, but it has also seen the development of novel beam manipulation techniques. While these new techniques can provide performance not traditionally achievable, they require specialized RF deflecting resonators to perform. In this talk, I will briefly review the basics of RF resonators and describe the properties and challenges associated with deflecting mode resonators. In this context, I will then discuss the application of these resonators in both existing and future nuclear, particle, and x-ray physics machines including CEBAF, PIP-II, APS, Mu2e, KEK-B, and the LHC at CERN.