An incomplete and ever-changing list.

Cross-platform

Things that I use on both MacOS and iOS/iPadOS.

Obsidian. "A second brain, for you, forever." The tool that I use to build this site. I also use it to keep a daily work log, project details, and technical reference.
- See also:
- Literate DevOps and Note Taking
Access .obsidian on iOS
Obsidian Plugins
Useful Obsidian Resources
Using Dataview
Obsidian

Zoom. No description necessary.
Slack. "I got 99 Inboxes but email ain't one."
Fantastical. The best calendar app.
Todoist. The Club at Macstories has published an Obsidian plugin that syncs to/from Todoist which is very nice.
1Password. Used to be the best password manager. I previously wrote that "[a]t time of writing we haven't seen how the somewhat controversial move to an Electron desktop client will work out. Keychain received a feature boost in iOS 15 and macOS Monterey that might make it good enough to be able to replace 1Password." We have now, and it hasn't been great. macOS Sonoma releases in a few weeks with a shiny new password tool. I am seriously considering moving, and, after almost 15 years, closing my 1Password subscription.
Stop the Madness. I've used this for a while on MacOS, and with the changes in iOS 15 it's now available on mobile too. Stops web sites from doing silly things like disabling copy & paste "for security".

CLI tools

bat. cat(1) with syntax highlighting.
delta. ~~A syntax highlighting pager for git and diff. bat is similar, but I think delta works better with git.~~ I've gone all-in with bat now, but delta might be more up your own street.
dog An improved dig.
fish. 2022 was my Year Of Using A Modern Shell. I've since gone back to zsh. Fish is great, but in a world of Bash and Zsh ubiquity, it added just a little too much friction. (Not to mention that I have been using Bourne-like shells for literally decades. That's a lot of muscle memory.)

Emacs. The Swiss Army Knife of text wrangling. I use emacs-plus on macOS.
Tower. To make Git friendly and usable.
iTerm 2. The best terminal app, but I have recently been trying Warp and finding myself decently impressed.
Archi. When I need to do some formal diagrams. The reuse that it enables, and the structure that it enforces, help me to make better diagrams.

Notability. For personal journaling and reflection.
Concepts. For documentation and diagrams.
Marvis Pro. The best music player. Super-configurable and it takes some effort, but you definitely get out of it everything that you put it.
Unsmartifier. Removes the annoying "Open in app" banners when you're using mobile Safari.
Working Copy. The Git client for iOS. Tight integration with iOS Files makes it even better.
Super Agent. Cookie pop ups? Not any more.
Noir. A Safari plugin that will apply a dark mode to web sites that do not already have one. I have this set to "When OS is set to use dark mode", and it works really well.

Shortcuts is an impressive automation tool. It hasn't had a great start on iOS 15 and Monterey, but it's still an essential part of my toolbox.

These utilities make Shortcuts better.

Jayson. JSON editing and viewing.
Scriptable. Javascript scripting with well written integration with Shortcuts and iOS.
Data Jar. Data store for Shortcuts.
Esse. Swiss army knife of text transformation for iOS and macOS. Not strictly Shortcuts-only, but it's where I use it.
GizmoPack. More shortcut actions to do things like signing JWTs and generating CSVs.
Toolbox Pro. Even more Shortcuts power tools. Honestly, some of these should be in Shortcuts, but they aren't, so this helps.