By poll-tax, yes I mean tax-per head. This was mooted in the UK in the 1980s to replace local ‘rates’ (essentially a local property tax) but there were literally riots over it, with people outraged that billionaires would pay the same as those who had no money, so the proposals were watered down a lot to include several ‘tiered’ bands of local property tax.
In terms of payroll taxes, these are not explicitly in the game, but considered for game purposes to be part of the regular income tax, Which is basically a progressive tax based on income. In the UK at least, the difference between National insurance (payroll tax) and Income tax is a mere technicality now, and there is a lot of talk about merging them entirely anyway. I’m not sure that separating them out in the game adds to the game enough to warrant the additional complexity it introduces, as perceptions towards, and effects of income tax and payroll taxes are extremely similar.
A couple I’d like to see, both health related.
Sports subsidies: Long term increase in health. Supported by patriots (see Team GB effect in Britain) - in fact, possibly even a slight increase in membership? Also parents; children’s football teams, etc. Opposed by capitalists on the same grounds as arts subsidies.
Cycle lanes: Decreases car usage. Long term slight increase in health. Moderate implementation time like bus lanes. Beloved by enviromentalist, commuter boost, rage from motorists. From experience, motorists really don’t like cyclists.
Both should fight obesity too 
And arguable increase environmentalist membership. People become greener when they breath in car fumes every day