Just check if Team Collaboration Lists feature activated? you can find this under Site Settings > Site features.
This feature enables Wiki Page Library, Links, Announcements, Calendar, Discussion Board, Tasks and few other templates.
If you still have the issue then the easiest way is by directly accessing create.aspx page which you can find user _layouts/15/create.aspx.
For SharePoint 2013: http://<site URL>/_layouts/15/create.aspx
For SharePoint 2010: http://<site URL>/_layouts/create.aspx