You never know when you might need a list of NamedSearches Siebel uses internally.
So, I thought to put it here along with some info where I've found it and some tips on how I usually use it. As you might've already guessed the main use of the list is to check you are not using these names with SetNamedSearch method in the production environment.

This comes handy when using eScript playground. For example, this is how you test an applet search spec without a compilation:

var bo = TheApplication().ActiveBusObject();
var bc = bo.GetBusComp("Account");
bc.SetNamedSearch("Applet Search Spec Named Search", '[Updated] > Today()-10');
bc.ExecuteQuery(ForwardBackward);

And below eScript snippet tells you all filters applied to an active BusComp if you don't feel like reading logs:

var bo = TheApplication().ActiveBusObject();
var bc = bo.GetBusComp("Account");
var aSpecs = [
    "System Search",
    "Applet Search Spec Named Search",
    "VisibilitySearch",
    "Link Search Spec Named Search",
    "PickListSearch",
    "Drill Down By Id Named Search",
    "Task UI Search Spec Named Search",
    "Content Targeting Named Search",
    "Sort Search Optimization",
    "Active Field Flag Search",
    "MVG Type Field Named Search",
    "Auxiliary Id Named Search",
    "Snapshot",
    "Bookmark Id Named Search"
];
if (bc.GetSearchExpr()) {
    log("User Search Spec", bc.GetSearchExpr());
}
for (var i in aSpecs) {
    var name = aSpecs[i];
    var spec = bc.GetNamedSearch(name);
    if (spec) {
        log(name, spec);
    }
}

Stay tuned and take care, folks!