Can I toot my own horn?

No? Okay, okay -- then Mike Perham from https://sidekiq.org is pretty great. I’d list others, but a lot of great single person businesses eventually turn into more than a single person business. And because of that, none come to mind right now other than Sidekiq.

(Currently trying to think of more...)

I'll claim there's no such thing. Any good business can benefit from having more people than 1. One would have to be deeply eccentric to refuse to hire anyone, even an executive assistant, to scale up the business.

Stratechery by Ben Thompson: https://stratechery.com/

some businesses sell dating & matchmaking services to the market of single people.

it might be hard to bootstrap such a business and compete with established competitors with major market share as the value of a matchmaking business surrounds growing a marketplace of people to offer many possible opportunities for matches to people who sign up (it might even be a bunch of different sub markets, some two sided, some one sided, etc).

i believe plentyoffish (founded by a single single person, iirc) tackled this by initially offering a free service without any revenue source, until the value of the business was realised by selling it with its large free userbase to an established competitor.

another downside of a dating & matchmaking business model is (at least for some segment of customers) if you succeed in making a good match for them then you remove them from your target market, and they cease being customers.

visualizevalue.com- Jack Butcher

Kiss- Yep, the band- Gene Simmons. he talks about how he runs it alone in Me. Inc: https://www.amazon.com/gp/product/B00I2PG3TW

define great