The problem with all this talk of a wealth tax is no one knows how it will be applied. And the moment it comes up, everyone assumes they're going to have to hand over 10% of the value of their house. This is preposterous.
Far more likely, it will be based on assets over a significant amount either cumulatively or by asset time.
Homes in which people live are likely to be exempt or, at most, might be taxed a percentage on the equity in those homes. [Because realistically, the entire financial system would collapse if the vast bulk of homeowners, with mortgages and homes valued at less than £1mn or whatever, suddenly had to free up capital].
The chances of pensions being included are, in my opinion, almost non-existent as it would cause the kind of outrage that is impossible to recover from . But other liquid assets are likely to be fair game w(with proviso above that it would depend on total existing wealth as above).
I've long maintained there are other taxes that could help the NHS - eg a minimum fee paid for all visits to GP. This could be waived on a mean tested basis for specific individuals but I think it's reasonable to say that the vast bulk of the population could afford a tenner when turning up to get our moles checked / asking about new contraception etc. You could also tax the wealthy by increasing VAT/tax for certain items - new cars, alcohol, holidays, homeware, appliances etc. Even clothing, certain food etc.
Personally, I think finding ways to close loopholes for tax avoiders - both personal and corporate - would be a much more useful tool. However, it's surprisingly difficult to do this. I worked on project linked to some work a tax lawyer had done for HMRC. His work was, on the surface, relatively minor and honestly, a sort of "duh - of course that's how it should work" project. And yet... it had been this absolutely massive project, with multiple lawyers etc etc because the tax system is so bloody complex. Finding ways to close loopholes for Amazon etc is, in my opinion, imperative*, but unlikely to be particularly easy.
*I love Amazon. I think they employ lots of people and facilitate many small businesses. If they are not legally obliged to pay tax, I completely understand why they don't. But I DO think that the UK government should be making it so that companies like them DO pay tax.