Yasser Saeed wrote: There are many cases where you need to have each clip on separate track above each other. One example is when creating collage effects like in this video:
As Jim already suggested.
1. Choose all the clips you want to place on separate tracks in a timeline.
2. In the media pool, right-click the selected clips and create a multicam clip. You'll have options to choose how the clips will be ordered within the multicam clip.
3. After the multicam clip is created, right-click it and open it in its own timeline. Multicam clips are a type of nested timeline, and the clips will be on separate tracks within it.
4. Select all the clips in the multicam clip's timeline, copy them, and paste them into your original timeline.
5. If you no longer need the multicam clip, you can delete it. That is it.

- sshot-1134.jpg (131.93 KiB) Viewed 536 times
This method is relatively fast and allows you to put clips on separate tracks. While a dedicated feature for this might occasionally be useful, it's unlikely you'll need to create collages with numerous tracks frequently enough to cause a significant problem. If that were the case, custom scripts could be created. In the meantime, the multicam clip workaround described above is an option.
Following that, if a video collage effect is desired, drag and drop the effect onto a clip, then copy and paste it onto other clips as needed, adjusting the settings for each.