Official cheatsheets:

• Keyboard shortcuts - MacOS
• Keyboard shortcuts - Windows
• Keyboard shortcuts - Linux

Multiple cursors at the beginning or the end of each line

• Select multiple lines (or whole document with CTRL + A)
• Press SHIFT + ALT + I to insert multiple cursors at the end of each line
• Press Home (FN + ← on Mac) once to jump to the start of each line (before first non-space character)
• Press Home (FN + ← on Mac) twice to jump to the beginning of each line
• Press End (FN + → on Mac) to jump to the end of each line