This is a small script I did for a project that would allow me to create instantly a random animation for objects floating in its place. Here is a small demo:
copy the code and paste it on the script editor on a Python tab. After that select the text and drag it to a custom shelf so you can use it. Position any object you want to animate in the place you want it to float and then press the shelf icon.
If you want to delete the existing animation (expressions conected to a selected object) to reposition the object and animated again you can use this other script. Just select object and aply script to delete the animation created.