Set Global Edit Mode to Gate ⌃⌥G — Logic Pro keyboard command of the day (KCotD)

shows the Step Sequencer Edit Mode menu with the 11 possible modes
  Set Global Edit Mode to Gate   ⌃⌥G

Sets the edit mode for all of the rows. Just like selecting ‘Gate’ from the menu bar control.

I really need to re-think my idea of step sequencing. Programming a sequencer using visual tools sparks lots of ideas.

Use Step Sequencer edit modes in Logic Pro — Apple Support

Gate: Drag vertically in the step to set the Gate value as a percentage of the step. The Gate value shortens the note length to less than the duration of the step.

Use Step Sequencer edit modes in Logic Pro — Apple Support

The Edit Mode selector in the Step Sequencer menu bar controls the edit mode for all rows in the pattern. Step On/Off mode is always available on the left-side button on the selector. You can choose other edit modes from the menu on the right side of the selector. The chosen edit mode appears on the right-side button. Edit modes include the following:

Repeat Regions/Events Multiple Times… — Logic Pro keyboard command of the day (KCotD)

  Repeat Regions/Events Multiple Times…

Make multiple copies (or aliases) of the selected region. Simple way to repeat sections of audio, or MIDI events

Repeat regions in the Logic Pro Tracks area — Apple Support

You can repeat one or more selected regions in the Tracks area. Repeating a region pastes one or more copies (or aliases) of the regions following (to the right of) the regions in the same track.

Double Cycle/Loop Length ⌥⇧⌘. — Logic Pro keyboard command of the day (KCotD)

  Double Cycle/Loop Length   ⌥⇧⌘.

Doubles the cycle length. The cycle area is lengthened in a forward motion. This becomes important if you change your mind and want to ‘Halve Cycle/Loop Length ⌥⇧⌘, — Halving shifts the start of the cycle forward in time. The only way to make the cycle smaller leaving the start position alone is by moving the cycle end mark backwards

Use the cycle area in Logic Pro — Apple Support

You can use the cycle area to repeatedly play a particular part of a project. The cycle area can be used for composing, practicing a part before recording, recording multiple takes, and other purposes.

Change loop settings for cells in Live Loops for Logic Pro — Apple Support

Loop Length: Determines the length of the loop. Changing the Loop Length value can be useful when you want to loop only a particular portion of a cell.

Toggle Cycle Preview ⌃C — Logic Pro keyboard command of the day (KCotD)

Shows the controls at the bottom of the Project Audio Browser window
  Toggle Cycle Preview    ⌃C

One of the many commands that have no particular documentation.

In the Project Audio Browser window there are playback controls. Play, Cycle, and Volume. The Cycle button is the named ‘Cycle Preview’ button.

When the Cycle is enabled the selected audio region will loop on playback.

Logic Pro Project Audio Browser interface — Apple Support

Cycle button: Loops playback of the selected audio file or region. Use in combination with the Play button.

Transpose -1 Octave ⌥⇧↓ — Logic Pro keyboard command of the day (KCotD)

  Transpose -1 Octave    ⌥⇧↓

Transpose the rows in the sequencer down an octave.

Logic Pro Step Sequencer overview — Apple Support

Step Sequencer is inspired by classic hardware step sequencers that have rows of configurable switches or knobs used to generate repeating musical patterns. In Step Sequencer, you create patterns by editing multifunctional steps in the step grid. Each row controls either a sound (which can be a drum kit piece, a note on an instrument, or a range of notes) or an automation parameter (letting you create automation changes over time in the pattern). Each step represents a definable length of musical time–by default, steps are of equal length, but you can change the length for individual rows or steps. You can adjust a wide range of parameters for individual steps, including velocity, pitch, gate time, and more; and edit pattern and row settings including pattern length, row loop start and end points, playback position, and rotation.