The search for dark matter requires two components: experiments seeking to detect it, and theories which can be constrained from the results of these experiments. Simplified Models present a useful avenue for investigating dark matter-Standard Model interactions, as they incorporate a minimal amount of complexity needed to probe high-energy interactions while remaining tractable. In my work, I investigate the use of the 2HDM+a/s Simplified Models to probe hypothetical interactions between Standard Model particles and Weakly Interacting Massive Particle (WIMP) dark matter. These models incorporate an additional Higgs doublet alongside the Standard model particles, as well as a scalar or pseudoscalar singlet particle that provides an interaction portal between Standard Model particles and WIMPs. These models also modify existing Standard Model interactions, and I investigate the constraints these processes can generate. I also investigate if these models can explain the recent detection of excess particles at a mass of 95 GeV at the LHC.