PowerPoint align by first selected shape
Override PowerPoint's default outermost shape alignment to instead align to the first selected shape
Temporarily override PowerPoint alignment to the first selected shape by Ctrl-clicking on the Powerpoint or PPT Productivity alignment button to align to first selected shape.
To permanently override alignment to the first selected shape, go to PPT Productivity tab > Settings > Shape Alignment, and tick "Align to first selected shape rather than outmost shape". Then use Ctrl-click and alignment temporarily returns back to the outermost shape for that button click.
Alignment overrides work on all PowerPoint alignment buttons, not just PPT Productivity. For example: Home ribbon > Arrange > Align > Align left/right/etc
Assign keyboard shortcuts to Alignment buttons
To assign shortcut keys, go to PPT Productivity tab > Settings > Shape Alignment, and tick "Align to first selected shape rather than outmost shape".
Then Shift-click on each alignment button to assign your shortcut key, or filter for commands named "FirstSelected" in the Shortcut Key Manager (PPT Productivity tab > Manage Custom Shortcut Keys)