Povidone-iodine (PVP-I) was the most studied mouthwash (14 in vitro and 9 in vivo studies), frequently showing significant reductions in viral load in vitro assays. Similarly, cetylpyridinium chloride (CPC) also showed good results, although evaluated in fewer studies. Chlorhexidine gluconate (CHX) and hydrogen peroxide (H2O2) showed conflicting results on SARS-CoV-2 load reduction in both in vitro and in vivo studies.
link
The study can be found here.