The extent of scope searches depends on the sources you have access to and the topic you are searching for.
Generally scope searches are run in CENTRAL and MEDLINE as a minimum. They can also be run in Embase (but read the information on RCTs and CCTs being added to CENTRAL from Embase before making a decision to do this).
Some Information Specialists also handsearch journals, journal supplements, conference proceedings and other sources.
You should also check the included studies of your group’s published reviews for relevant studies to add to your register.