[DennisP]

Could always tax other things, like consumption, inheritance, or carbon emissions.

[adrianN]

Consumption taxes hit poor people harder than rich people. Inheritance might work, and carbon emissions might also work if you have a tax-and-rebate system so that poor people can still afford stuff.

[DennisP]

Consumption taxes can give rebates just like carbon taxes. A somewhat popular national sales tax proposal a few years back would have done it that way.

https://en.wikipedia.org/wiki/FairTax