My Zettelkasten and secure note-taking tool is Passfindr.
My sketch book is a Moleskine notebook.
Most of my notes are URLs, micro-notes, ideas, login credentials for online and other accounts, addresses and everything between. Lots of micro documents. Some of the notes are 20+ years old. Finding these notes and finding them fast is crucial. Passfindr does that with ease and I get information faster than anything else. Fast searching/finding matters. Once you get the idea behind the internal about: commands, you can even enhance the searching and finding capabilities and build your own Zettelkasten.
double square bracket notation : this is exactly how Passfindr https://passfindr.com implements linking to other notes. Passfindr has a powerful search and searching can be inlined in notes like [[search term including tags, regexp, etc.]].
Easy cross-linking notes and the ability to categorize with tags are essential to note taking apps. A fast and powerful search is as much important. If the note taking app can be turned into a Zettelkasten system, then you definitely should have a more detailed look at the app. https://passfindr.com does exactly this. Passfindr also lets one encrypt user generated content so it can be used as a password/secrets store as well. It needs to work on every internet enabled platform and devices. So your choice must be the best maintained application: the web browser.
As an everyday user for my micro documents, articles, secrets and all kind of resources and ideas, I'm definitely not tired of Passfindr.
Cheatsheets are a very helpful resource and you need to have a tool to keep, interlink, retrieve and organize them. A physical notebook is not the optimal choice because of some limitations like fast retrieval of topics and almost impossible filtered searching etc.
Organize your "new things" and resources to cheatsheets in a Zettelkasten like tool. You can use a simple text editor or there are applications and plug-ins available to get a Zettelkasten-like app. I personally use Passfindr (https://passfindr.com), a freemium Personal Information Manager with powerful and fast search capabilities.
I rely on the built in password generator of Passfindr https://passfindr.com using the same random number generator as mentioned in correcthorse.pw. When using a Password Manager, and one should, different passwords for every internet account is straight forward.
Most of my notes are URLs, micro-notes, ideas, login credentials for online and other accounts, addresses and everything between. Lots of micro documents. Some of the notes are 20+ years old. Finding these notes and finding them fast is crucial. Passfindr does that with ease and I get information faster than anything else. Fast searching/finding matters. Once you get the idea behind the internal about: commands, you can even enhance the searching and finding capabilities and build your own Zettelkasten.