I'm running into a problem trying to remove a family from a project. I'm able to delete the family types but it seems like the family is still loaded in the project. Is there a way to remove it completely?

so far, i've looked at these sources:

1) https://adndevblog.typepad.com/aec/2012/07/supported-workflow-for-unloading-a-family-using-the-revit-api.html

2) https://adndevblog.typepad.com/aec/2012/07/supported-workflow-for-unloading-a-family-using-the-revit-api.html

here's my code:

FilteredElementCollector colTitleBlocks = new FilteredElementCollector(doc)
                .OfClass(typeof(FamilySymbol))
                .OfCategory(BuiltInCategory.OST_TitleBlocks);


using (Transaction tx6 = new Transaction(doc))
{
    tx6.Start("load custom titleblock that you just made");


    Element family2Unload = null;
    foreach (FamilySymbol xfamily in colTitleBlocks )
        {

        if (xfamily.FamilyName == "E1 30 x 42 Horizontal")
             {

             family2Unload = doc.GetElement(xfamily.Id) as Element;

             }
        }
   doc.Delete(family2Unload.Id);

   tx6.Commit();
}

Families

FamilyInstance => a placed instance of a family

FamilySymbol => a family type with 0-m instances

Family => A family with with n types 0-m instances

Example : FamilyDelete.pushbutton

Here is one of my script from pyRevitMEP to delete families :

"""
Copyright (c) 2017 Cyril Waechter
Python scripts for Autodesk Revit
This file is part of pypevitmep repository at https://github.com/CyrilWaechter/pypevitmep
pypevitmep is an extension for pyRevit. It contain free set of scripts for Autodesk Revit:
you can redistribute it and/or modify it under the terms of the GNU General Public License
version 3, as published by the Free Software Foundation.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.
See this link for a copy of the GNU General Public License protecting this package.
https://github.com/CyrilWaechter/pypevitmep/blob/master/LICENSE
"""
import rpw
doc = rpw.revit.doc
uidoc = rpw.revit.uidoc

from Autodesk.Revit.DB import Transaction, FamilySymbol

__doc__ = "Delete selected families from project"
__title__ = "Family delete"
__author__ = "Cyril Waechter"
__context__ = "Selection"


with rpw.db.Transaction("Delete families from project"):
    # Find families of selected object and delete it
    for id in uidoc.Selection.GetElementIds():
        el = doc.GetElement(id)
        family_id = el.Symbol.Family.Id
        doc.Delete(family_id)

You have the same one for family types : FamilyTypeDelete.pushbutton