Enumerable.Cast<T>次のメソッドでこれを行うことができます。

List<bool> bools= GetBoolList();
IList<Object> objects= bools.Cast<Object>().ToList();

The non-LINQ way to do this is with List.ConvertAll:

List<bool> b = new List<bool> { true, false, true };
List<object> o = b.ConvertAll(x => (object)x);

Since this method knows what size to make the new list, it is likely to be faster than the LINQ version for large lists.

List<bool> list = new List<bool>{true,true,false,false,true};
List<Object> listObj1 = list.Select(i=> (Object)i).ToList();// First way
List<Object> listObj2 = list.Cast<Object>().ToList();// Second way 
List<Object> listObj3 = list.OfType<Object>().ToList();// Third way 

Following is to test quickly in linqpad

 list.Dump();
 listObj1.Dump();
 listObj2.Dump();
 listObj3.Dump();