Hmm there's a lot of them. Most of the episodes are SAAS apps but I remember Dan from Real Python[0] in an earlier episode having a pretty rigorous set up for solo developing his platform. It gets a few million monthly page views. He happens to use Heroku tho, so that episode is pretty dev heavy vs ops.
The GoRails[1] episode is a good example of keeping it simple but killing it. It's just one dude who built a million dollar business hosting everything on a $20 a month DigitalOcean server, and the server itself hums along at a few percent load while having tens of thousands of members.
Jake from SongRender[2] is a solo SAAS app project for building audio visualizer videos with Node, it's not running at massive scale but he did everything himself -- including setting up blue / green deploys with Terraform.
Cory built a service to create and design placecards[3]. I remember this one focusing on keeping it simple while still being able to run a profitable SAAS app.
If you're looking for intergalactic crazy scale, an engineer from Dropbox[4] was on a few months ago but that's not a solo dev platform.
Another SAAS app and large scale deployment was Mux[5]. They handle billions of video API requests a month with a pretty small team.
It's hard to only recommend a few because often times you can get at least 1 nugget of information out of each episode and apply it back to your set up. One takeaway from a lot of solo dev projects is they just ship something and keep it simple until that stops working. You'd be surprised at how far you can go with 1 server, handling tens or hundreds of thousands of monthly visitors but still generate enough profit from your project to make it a full time income or at least be a nice chunk of side income.
[0]: https://runninginproduction.com/podcast/4-real-python-is-one...
[1]: https://runninginproduction.com/podcast/12-learn-ruby-on-rai...
[2]: https://runninginproduction.com/podcast/83-songrender-lets-y...
[3]: https://runninginproduction.com/podcast/39-place-card-me-let...
[4]: https://runninginproduction.com/podcast/82-dropbox-gives-you...
[5]: https://runninginproduction.com/podcast/31-mux-is-an-api-bas...