What side hustles have you personally seen work pretty well?
Corporations taking over side hustles seems to be screwing over people, since they take such a large cut and flood the market for that hustle.
But the ones I've personally seen people do that work pretty well (in USA) are:
Stay at home mom watching another kid (legally dubious depending on state/situation. But I ain't no narc.)
A neighbor of my mom's sends out a menu saying what she plans on cooking each night for that week, and for $X will deliver you some as well (Legal in Utah due to special laws, other states could be dubious. )
People who go pick up free furniture that is pretty trashed, and then refurbishes it and sells it. Or people with trucks who are like "Will deliver furniture for $30 in X area" is also pretty life saver for people without cars/trucks. Was able to get a super cheap/nice coach because of this.
People who just flip free stuff or stuff from thrift stores without doing any improvements annoy me greatly though. We broke and you're just driving up the price!
None of these generate a ton of cash, but I like that they take very little up front cost, aren't disruptive, and mostly take labor.
I've "debated" doing that, since I'm debt free aside from mortgage and have a good credit score, so I could probably open enough cards to get the cycle moving. But the research to find the best hidden gems of reward programs is probably hard.
Other thing I've seen people with great credit scores do is basically put EVERYTHING on 0% intro credit cards, pay minimums, save all the money in a HYSA or a mutual fund, then pay off the balance right before the 0% ends, and then open a new 0% card and repeat. Which seems finicky, but basically gives yourself a 4-8% raise if you set it up to just take care of itself automatically.