Grip it Pad
Surface

"This product was recommended by a friend. When he showed it to me at a wedding that he was DJ'ing I knew right then that this was a good product. I use it on my portable Western Digital 1 TB drive. I DJ, so now I can mount my drive on a table or on the edge of my laptop and I don't worry about it sliding around. Two come in the package so I put the other on the bottom of my other portable hard drive. I purchased another set of these and put two of these on the bottom of a full size hard drive."  3/2016

"Works great for a Samsung SSD and portable HD, and attaching it to the back of a macbook pro.

It provides extra padding for hard drive when not in use, and makes it a lot easier to work on my laptop while plugged into an ssd. I'm using a Samsung T5 and Seagate Backup Slims"  3/2018 

"I added these pads to my MacBook Pro because I was tired of losing my grip. Worked like a charm!"  8/2019

Amazon - VINE VOICE  1/2019

"Not cheap - but do the job.

I put a slip pad under the dashboard mount for my Garmin GPS unit. I had been having a lot of problems with it sliding off when I accelerated. This pad fixed the problem."

1. Yes you can, I used it with my phone. 
2. Very easy to cut down for other electronic devices. I use it for all my smartphones.
3. Yes, one can definitely cut it very easily to any shape or size. 

"I use it to attach a 3TB portable hard drive right on the lid of my MacBook Pro, which has only limited memory being solid state. Now I have plenty of memory for editing video and music. Before, I was constantly having to clear off the drive -- sometimes between every project. It may not be slick and pretty, but it sure is functional."  6/2016

“Product works great. I have two remote disc drives with them now and two more to do. These unpowered drives have nothing to keep them from sliding freely and these pads prevent that. Great! J”   1/2019