Hello Timo79,

There are a couple of ways to do this.

The best way is to group the object to itself. (select the object, then press ctrl g) Now the object will have a new axis placed at the center of the grid. You can move this Axis where ever you like in the scene, and use it as the objects pivot. Now if you want to use the Objects original axis, you can simple press the down arrow key on the keyboard to toggle to it, and press the Up arrow key to toggle back to the new Axis. There are other ways to do this, but this is the easiest.

To file through all the objects in the scene. Simply select one object (in object mode) and use the Left and Right arrow keys to file through the scenes Hierarchy. Use the Up and Down arrow keys to Brake in and out of groups. You can also use the Outliner to easily, browse, and select objects in your scene.