Thank you! I was pretty surprised that nothing like Mathesar existed already.

Unlike SequelPro and TablePlus, we're a web application (although we do want to do a desktop version eventually). And Mathesar works even if you don't have an existing DB to connect to – you can set up a DB from scratch during installation.

https://github.com/beekeeper-studio/beekeeper-studio is pretty decent.

tableplus is freemium like. in the free version can have 2 tabs open. it also works with way more than postgres.