Each one does a single job, runs entirely in your browser, and asks nothing of you. No account. Nothing uploaded. Works offline once loaded.
Every tool is a single page of HTML and JavaScript. Your data stays on your device; there is no server to send it to. If a tool ever needs one, it will say so on the page before you type anything.
Some tools sit next to a paid kit that does the rest of the job — templates, checklists, the boring paperwork. The tool is complete without it.