Idea for ID

I have two worksheets where names can be same for several things.
I want to create unique list at beggining so I can vlookup by that list...

I could put in first columns rows like: 1,2,3,4...end but I would like to avoid it and use something instead, but also need to be logical...

My first idea is to use octal numbers, but I'm not very happy with that solution since it still have something as 1,2,3,4,5...
But it would be harder to trace it...

Any more ideas?