Wealth taxes and land value taxes seem like the most sane way to fund social programs. Extract a bit of value from the people who have runaway wealth (but not so much that their wealth can't continue to grow), and use it to help the economically downtrodden become more upwardly mobile (education, healthcare, basic social safety nets.)

Pair it with a hefty pigeuvian carbon tax and you could probably do away with income taxes entirely.

(A nondistortionary VAT to replace sales taxes and corporate income taxes would be nice as well.)