Actually, UBI has been proposed many times by many high profile economists, you should be able to find these yourself. Yes, there are economists and economic thinkers from a long time back that advocate wealth taxes, or similar, or partial implementations of it. You should be able to find these too. I'm not going to help you because you come across as rude and ignorant.
No amount of income tax, no matter how progressive, or capital gains tax (also a tax on deltas), etc, can act as a wealth cap. Simple logic should prove this to you. A multi-billionaire dies, his son inherits 10 billion dollars, you apply 99% tax to anything over $1 income or capital gains made on everyone, and your guy is still a multi-billionaire for life. It just makes sure that the poorest, no matter how much skill or value they ever bring to society, can never make more than a small amount of savings. Is this your aim? If not, you haven't thought through the problem.
Estate taxes are somewhat similar to wealth taxes though, except they apply only once, when a rich person dies. So, the rich person will be rich forever, no matter how little he brings to society. His children will be rich too, but some tax goes to the state, to make up for their 'unearned' income.
A wealth tax is more like a continuous version of an estate tax, that happens throughout the person's life. However, an estate tax does not encourage behaviour of making wealth productive on the individual. Mostly it encourages the creation of trust funds and such to avoid the tax for the benefit of their offspring. A wealth tax means that a person must invest their wealth (on average) in a productive (and therefore beneficial, under the assumptions of a free market) manner, at all times. The idea is not to disallow, but to discourage, large amounts of wealth to only be a benefit to the holder of the wealth and not society in general. A wealth tax makes it a benefit to society in general.
Let's say you have a $2B luxury mansion property. You live very well on it, and make a tiny bit of money so you cover all your spending, but only the minimum. You die, and your child inherits it, but has to pay tax, we give half of it to the state, leaving the with a $1B luxury mansion property, and that person can make a tiny bit of money off of it to cover their spending, but only the minimum. Pretty much that $1B worth of WEALTH, is locked up by one person to the exclusion of everyone else for their entire lifetime. For that one person it is great, but for everyone else, it provides nothing.
In a 1% wealth tax scenario, that $2B mansion better be making at least $20M/year to cover it's taxes, which benefit society directly, or it is a losing proposition and should be sold to someone who can make productive use of it. Also, over the average lifetime of a human being, they will pay the equivalent of an estate tax for that wealth, but the difference being, wealth would have been (more likely) to be used productively, and more efficiently, over that time, rather than simply hoarded.
Now, you see if you can find the economists who have proposed these ideas before. Okay?