Ask HN: Best Passive Income Method?

I am learning Python. I want to create some passive income streams while learning Python. I have free time available around weekends.I am working on few ideas of my own, but those will not necessarily generate income.

Which method of the following would you recommend?

ebook in a niche technical topic SaaS product that solves a niche issue mobile or web based game

Use commas! ,,,

Invest in startups as a technical advisor. This has 2 effects: you will grow your network, and you will help the ecosystem. Those two, only my opinion, compound better than whatever financial instruments you can think of.

OP's comment doesn't read to me as though that's what they're asking for - they mentioned three potential high-level approaches and are asking for thoughts re: each of those relative to one another.

One route to success is to take some other domain that you have expertise in, that most software devs aren't familiar with. Come up with an application that solves a problem in that domain, then market to those people.

Here's a simple example (this probably won't make any money, but it is good for illustrative purposes). If you look at an egg carton, there is a sell by date on there, but it doesn't list the date that the eggs were laid. Well it does, but not directly. There is a number on it which is the day number of the year (1 - 365), that represents when the eggs were laid.

So come up with an app, called "fresheggs", that just converts this number to a date, and will tell you how many days old these eggs are. Add location info to the app, and put in ads at the bottom that are coupons for the store you are in. You get paid when a user clicks on and uses that coupon.