For the past year and a half, I've been focused on just one side project: a privacy-friendly personal finance simulator that doesn't ask to link your accounts (projectionlab.com), can run Monte Carlo simulations in your browser, and keeps your data client-side unless you choose otherwise.
Randomly came across your comment on this thread and took a few minutes to check out your sandbox env. Could totally see something like this taking off or getting bought out by a bank/Intuit/etc.
I may be a bit biased since I'm huge into personal finance, but hopefully you can target that segment and carve out a solid set of paying customers