<ctrl-O> - to open a note.
The fuzzy finder makes this super fast,
if you name your notes in a way you'll remember later (SEO!).
<ctrl-E> - switch between reader and edit mode
(I almost always edit with external editor (Vim) any way,
so I nearly always want the note in reader mode.
In settings, you can make this the default)
<ctrl-shift-v> - (custom binding) open current note in external editor
I'd recommend going into settings/options and having a look at the "Hotkeys" tab. There's a lot of things that aren't currently set, or default hotkeys that might be useful to you, like:
Toggle pin - (not set by default) I set this to ctrl + shift + p which pins the current tab so it can't be replaced with another tab
Close current tab - By default it's set to ctrl + w
Command palette - opens the command palette. By default it's set to ctrl + p. The command palette is amazing because it shows you everything in the "Hotkeys" tab. So you don't even need a hotkey set to use something. Like you can open the command palette and search for "release notes" and it will show you the current release notes. If you have the emoji plugin installed, you can open the command palette and search for "emoji" and it will open the emoji toolbar.
Quick switcher - search by note title. By default it's set to ctrl + o. But I have the Omnisearch plugin installed so I set this hotkey to that instead.
The plugin QuickAdd is really useful here as well, you can create your own hotkeys. I made one so when I press ctrl + n it creates a new note in a specific folder with today's date and time as the file name, so I can quickly write something down.