specific list of entities

Actually it's pretty easy, just change the first section of your standard scan.

replace
[type = Stock]
and [country is US]

with
[favorites list is 118] // Watch ETF

(note: list 118 just happens to be one of my lists, yours will be different)

Here's a more detailed blog article on the whole subject.

http://stockcharts.com/articles/scanning/2015/02/Scan-My-Fav-Lists.html?st=scan+chartlist