There is: https://www.dmachoice.org/ https://www.dmachoice.org/. It took quite a while (several months) until I noticed any changes, but my (very subjective) im

There is: https://www.dmachoice.org/ https://www.dmachoice.org/. It took quite a while (several months) until I noticed any changes, but my (very subjective) impression is that the (spam) mail volume decreased over time. Another thing I'd suggest is https://donotcall.gov/ https://donotcall.gov/. Registering there seems to have had a positive impact on the number of spam calls I receive.