I think a lot of people think of "no-code" tools as something exclusively for non-developers; things like Webflow and Bubble for creating apps. I don't think that's ever really been the case, Zapier being a great example of that, but there's been a lot more tools coming to market in the past couple years that actually work well as a way to replace tedious code-based workflows. i.e. Use Retool instead of building UIs for internal apps, use Reflect to build automated tests instead of Selenium, etc.
All of what I did with Zapier could have been implemented with a database, a bunch of scripting, and cronjobs, but using Zapier saved oodles of time and meant I was outsourcing the maintenance to their API integrators rather than to myself.
I was able to do so much with triggers and webhooks I can only imagine what is possible now with their more recent code blocks feature and adding better environment variables.
WordPress, Squarespace and Wix... As their userbases dwarf all other systems mentioned
Not sure where it would fit in, but Looker adoption is crazy. It's deeper though: no-code data modeling
9) Online DB tools -> Quickbase, Airtable, Knack, etc 10) Website builder -> webflow, softr, etc
Surprised I haven't come across one yet...
1) BPM tools: build workflows & business processes. Tools like Appian, Pega, kissflow, etc
2) Form builders: jotform, typeform, etc
3) automation: Zapier, integromat, etc
4) Frontend builder - Consumer apps -> bubble, adalo, etc - Internal apps -> Retool, DronaHQ, Appsmith
5) App builder - Build core business apps (including backend, microservices , etc) - Outsystems, Mendix
6) Field force apps -> prontoforms, fulcrum, etc
7) Extension builder -> extension.dev
8) Test automation -> reflect.run
Disclaimer: I am part of DronaHQ.