Check out the following cheat sheets to get an overview of the macOS shortcuts.
Sheet and Group Handling
New Sheet: ⌘N
New Group: ⇧⌘N
New Filter: ⌃⌘N
New Window: ⌥⌘N
Open from Library: ⌘O
Open from Current Section: ⇧⌘O
Open from Current Group: ⌥⌘O
Select Previous Sheet: ⌥⌘↑
Select Next Sheet: ⌥⌘↓
Reveal Sheet in Group: ⌘↩
Add Sheet to Favorites: ⌃⌘U
Show/Hide Favorites: ⇧⌘U
Save Version: ⌘S
Duplicate Sheet: ⌘D
Move Sheet/Group to Trash: ⌘⌫
Erase Sheet/Group: ⌥⌘⌫
Glue/Unglue Sheets: ⌘J
Force Copy Sheet/Group: ⌥Drag
Force Move Sheet/Group: ⌘Drag
Copy x-callback-url: ⌘C
Editor
Smart Paste: ⇧⌘V
Copy as Markdown: ⌥⌘C
Paste as Plain Text: ⌥⇧⌘V
Paste from Markdown: ⌥⌘V
Move Paragraph One Line Up: ⌃⌘↑
Move Paragraph One Line Down: ⌃⌘↓
Split at Selection: ⇧⌘B
Export Preview: ⇧⌘P
Refresh Export Preview: ⌘R
Print Editor View: ⌘P
Search in Sheet List: ⇧⌘F
Show Find Panel: ⌘F
Show Find and Replace: ⌥⌘F
Jump To Next/Previous Match: ⌘G / ⇧⌘G
Show Spelling and Grammar: ⌘:
Start Dictation: fn fn
Emoji & Symbols: ⌃⌘Space
Insert Line Break: ⇧↩ or ⌃↩
Syntax Selection in Code Block: ⌘↩
End Smart List/Code Block: ⌥↩
Move Focus to Sheet: ⌘← ⌘←
Markup
Increase Heading Level: ⌘# or ⌘\
Decrease Heading Level: ⇧⌘# or ⇧⌘\
Mark as Strong: ⌘B
Mark as Emphasis: ⌘I
Mark as Link: ⌘K
Clear Markup in Selection: ⌘L
View
Enable/Disable Typewriter Mode: ⌥⌘T
Show/Hide Library: ⌘1
Show/Hide Sheet List: ⌘2
Show Editor: ⌘3
Show/Hide Dashboard: ⌘4
Show/Hide Quick Export Panel: ⌘6
Show/Hide Statistics Panel: ⌘7
Show/Hide Navigation Panel: ⌘8
Show/Hide Markup Panel: ⌘9
Open Overview in Dashboard: ⌃⌘1
Open Progress in Dashboard: ⌃⌘2
Open Outline in Dashboard: ⌃⌘3
Open Annotations in Dashboard: ⌃⌘4
Open Attachments in Dashboard: ⌃⌘5
Jump to Keywords Section: ⇧⌘K
Default Text Zoom Level: ⌘0
Increase Text Zoom Level: ⌘+
Decrease Text Zoom Level: ⌘-
Toggle Light/Dark Mode: ⌥⌘L
Toggle Light/Dark Theme: ⌥⌘X
Step-Through Views: ⌥⌘←/⌥⌘→
Step-Through Dashboard Sections: ⌃⌘ ←/⌃⌘→
Window Management
Minimize Window: ⌘M
Enter/Exit Full Screen: ⌃⌘F
Zoom Window: ⌃⌘Z
One Shortcut to Find Them All
Search for Menu Actions: ⇧⌘/