Align Tools handles a focused task in Blender: aligning selected objects to the active object. You'll find it in the 3D Viewport under Sidebar → Item Tab, which keeps the controls within reach while you work in the scene.
The add-on was originally part of Blender 4.1's bundled add-ons and is now distributed as a separate extension, offered as-is with limited support. It was created by gabhead, Lell and Anfeo, and is released under the GNU General Public License v3.0 or later. On the Blender extensions platform it sits at popularity rank 29.
The current release, version 0.3.6, ships a bugfix for advanced mode. Align Tools is compatible with Blender 4.2 LTS and newer, and requires no special permissions. It's listed here as free; check the developer's page for current licensing details.