Shadow IT is an unsupported, unendorsed IT process. Like when an office (without official support, and possibly against official rules) uses MS Access + VBA + whatever to automate a business process. ChatGPT is not endorsed by a lot of offices (in fact it's discouraged by many because it's an easy way to exfiltrate proprietary or otherwise confidential information since OpenAI retains those inputs), but it's become a part of a lot of people's workflows.
Salesforce is oddly popular as a Shadow IT platform for web applications because it has a database and a programming language, but is often controlled by "non-IT" teams such as finance or whatever.
I'm seeing people migrate perfectly fine ASP.NET or JSP applications to Salesforce just to get away from their internal IT teams, which can stretch out the paperwork to 2-3 years just to spin up a VM for a legitimate purpose.
God. Migrate to Salesforce was exactly the idea brought up by the sales side at a job of mine. I was on the IT side. Thank god we talked them down (plus they got sticker shock).
Some sales asks were legit and we got 'em done. Some were legit but low ROI and never done/priority even as sales had majority say in those priorities. Some were "please take this customer-hostile, flaky, human-explicitly-in-the-loop CRM workflow that has the thinnest veneer of plausibility above pure gaming of KPIs and insert it into a core product flow that's working well".
I think low code tools will continue to proliferate and I'm not against it. I do think they will be an interesting test of how much and in what contexts consumers are willing to accept half baked solutions. The capital environment this past decade has meant corporate leadership has been able to touch hot stoves without getting burned. Often they've been rewarded for it.
That entire list is bananas. Not one mention of PowerAutomate or BI? Sticking within the typical Microsoft stranglehold offers a fair amount of tooling with multiple integration points. They come bundled with everything else in a corporate environment, so they are "free" and less intimidating for a non-technical person to dip their toe into than any other low-code tool.
This list is shadow IT, which means the things that the corporate IT department isn't paying for and often doesn't even know about. The tools you mention are in the Productiv (and Okta) data in a different category.
https://en.wikipedia.org/wiki/Shadow_IT