List Template ID

List of ListTemplated Id are given below.

100 Generic list
101 Document library
102 Survey
103 Links list
104 Announcements list
105 Contacts list
106 Events list
107 Tasks list
108 Discussion board
109 Picture library
110 Data sources
111 Site template gallery
112 User Information list
113 Web Part gallery
114 List template gallery
115 XML Form library
116 Master pages gallery
117 No-Code Workflows
118 Custom Workflow Process
119 Wiki Page library
120 Custom grid for a list
130 Data Connection library
140 Workflow History
150 Gantt Tasks list
200 Meeting Series list
201 Meeting Agenda list
202 Meeting Attendees list
204 Meeting Decisions list
207 Meeting Objectives list
210 Meeting text box
211 Meeting Things To Bring list
212 Meeting Workspace Pages list
301 Blog Posts list
302 Blog Comments list
303 Blog Categories list
1100 Issue tracking
1200 Administrator tasks list

Example : The following example is a console application that retrieves data from all lists that are based on

the Contacts list template.

using System;
using System.Data;
using Microsoft.SharePoint;

namespace Test
{
   class ConsoleApp
   {
      static void Main(string[] args)
      {
         using (SPSite site = new SPSite("http://localhost"))
         {
            using (SPWeb web = site.OpenWeb())
            {
               SPSiteDataQuery query = new SPSiteDataQuery();

               // Query all Web sites in this site collection.
               query.Webs = "<Webs Scope=\"SiteCollection\">";

               //Ask for all lists created from the contacts template.
               query.Lists = "<Lists ServerTemplate=\"105\" />";

               // Get the Title (Last Name) and FirstName fields.
               query.ViewFields = "<FieldRef Name=\"Title\" />"; 
               query.ViewFields += "<FieldRef Name=\"FirstName\" Nullable=\"TRUE\"/>";

               DataTable results = web.GetSiteData(query);

               foreach (DataRow row in results.Rows)
                  Console.WriteLine("{0} {1}", row["FirstName"], row["Title"]);
            }
         }
         Console.ReadLine();
      }
   }
}

Example2:

merge two identical SharePoint Lists into one list?

using (SPSite site = new SPSite(url))
{
    using (SPWeb web = site.OpenWeb())
    {
        SPList usersList1 = web.Lists[strListName1];
        SPList usersList2 = web.Lists[strListName2];
        SPList mergeList = web.Lists[strMergeList];

        ..loop through list 1, check if item in list 2, if it isn't add to merge list

        ..loop through list 2, check if in merge list, if it isn't add to merge list

        mergeList.Update();
    }
}