Grignard reagent with sulfur dioxide
You get sulfinic acids $\ce{RSO2H}.$

This paper by Dowson et al. [1] states that Grignard plus $\ce{SO2}$ gives sulfinic acids and as a reference quotes an older article by Allen Jr. et al. [2] which states


  The reaction between sulfur dioxide and Grignard reagent has been widely used for the preparation of aromatic and aliphatic sulfinic acids. 


I would suggest you read [2] and the references it quotes.

References


Dowson, G. R. M.; Dimitriou, I.; Owen, R. E.; Reed, D. G.; Allen, R. W. K.; Styring, P. Kinetic and Economic Analysis of Reactive Capture of Dilute Carbon Dioxide with Grignard Reagents. Faraday Discuss. 2015, 183, 47–65. https://doi.org/10/gf9hvn. (Research Gate — PDF)  
Allen, Jr., Paul.; Rehl, W. Richard.; Fuchs, P. E. Sulfone Formation during Sulfination of the Alkyl Grignard Reagent. J. Org. Chem. 1955, 20 (9), 1237–1239. https://doi.org/10/d42z3x.