The BioCheck app written by Kay Knight (https://apps.wikitree.com/apps/sands1865/biocheck/) is a good way to search for text in profiles on your watchlist.
To use it:
1. In the "How to find profiles" box, select "Check watchlist"
2. Change the "Max search profiles", "Max to check" and "Max profiles to report" numbers to be at least the number of profiles on your watchlist.
3. In the "Search biography for" box, enter the phrase you want to search for.
4. Press the "Check Profiles" button.
In the results, the "Search?" column will say "Found" for each profile that contains the text you searched for.