What's an example of good people doing good things, which is not an act of harm reduction or mitigating some kind of evil?

Teachers.

You think education doesn't keep evil or harm at bay?

Scientists just trying to make us all smarter.

Doctors helping their patients.

Honestly you could apply this to a lot of people just going through their daily job.

Open source software maintainers.

People who put their shopping carts away.

I am a firm believer in the Shopping Cart Theory.
- What theory?
I wouldn't call that doing good. That's the bare minimum for participating in society; those who don't are actually evil.

Old men planting trees in whose shade they shall never sit.

Reduces or mitigates skin cancer?

Edit: and air pollution?
- They aren't planting them to reduce skin cancer, though. Every action has some positive and negative aspects; you have to look at the intentions.

open source contributors.

I'd say good old fashion politeness like saying good morning, giving someone a (real) compliment, and other small random acts of kindness. You do it because you want to not because you expect something.

The lady at work who brings in a shopping bag full of chocolates and lollies once in a while just to make us stupidly happy and giggly.

People who seed

Oh wait you're talking about torrents...
- I assumed they meant plants.

Good public art.

Being a reciprocal lover

I'll hold a door for a body going the other way.

Sometimes, I'll even let a truck merge.

One time I cut someone off in traffic by accident and they ended up behind me in a drive thru so I bought their coffee.

I'm no saint tho. I still fart in elevators.

I once vomited in an elevator. Sorry to whomever had to clean that up. I was sincerely ill and had to get home to bed & toilet asap.

Being nice to my partner. Other people. Inviting them for dinner. Caring for children or neighbors.

Medics and nurses, when the patients aren't terminally ill (harm reduction). Whether they're "good people", and how often they do their jobs right can be debated, but properly caring for the sick is a good thing to do.

If we conceive of ethics as rooted in duty or virtue, rather than outcomes, we can then argue that simply doing your duty or being virtuous are good regardless of whether they lead to harm reduction or mitigation. The people here who have suggested just doing your job well (a duty) or being polite (a virtue) are putting forward a model of ethics based on these ideas.

Working to understand the universe

helping people