The following are all Windows keyboard shortcuts that use the Ctrl key:

GENERAL

Ctrl + A: Select All
Ctrl + C: Copy
Ctrl + X: Cut
Ctrl + V: Paste
Ctrl + Z: Undo
Ctrl + Y: Re-run
Ctrl + F: Search
Ctrl + H: Find and Replace
Ctrl + N: New Document/Window
Ctrl + O: Open
Ctrl + P: Print
Ctrl + S: Save
Ctrl + W: Close Window
Ctrl + F4: Close the active tab or window
Ctrl + Alt + Del: Task Manager
Ctrl + Shift + Esc: Open Task Manager directly
Ctrl + Shift + T: Reopen the last closed tab in a web browser
Ctrl + Esc: Open Start Menu
Ctrl + F10: Activate the menu bar in a window

Navigating and editing text

Ctrl + B: Make text bold or format
Ctrl + I: Italicize or format text
Ctrl + U: Underline or format text
Ctrl + L: Align text to links
Ctrl + R: Align text to the right
Ctrl + E: Center Text
Ctrl + J: Align text on both sides
Ctrl + K: Insert or Edit a Hyperlink
Ctrl + D: Duplicate Text
Ctrl + F3: Add a selected word or phrase to the clipboard for quick reuse

Windows, desktop, and screens

Ctrl + F5: Refresh the screen
Ctrl + F6: Switch between open windows of the same program
Ctrl + F12: Print Document
Ctrl + Shift + N: Create a new folder
Ctrl + Shift + Arrow Keys: Select text in words or paragraphs
Ctrl + Alt + F: Open the “Search for computers” option
Ctrl + Alt + F4: Closing the current task
Ctrl + Alt + Tab: Switch between open windows
Ctrl + Shift + Esc: Open Task Manager
Ctrl + Shift + T: Reopen the last closed tab in a web browser

The exact keyboard shortcuts may vary depending on the version of Windows or the program that is being used.