1. Keyword Stuffing or Keyword stacking: In this a SEO Professionals uses the all keywords in their web page content in excessive way from the SEO point of view not user point of view.
2. Spammy footer links and tags: a SEO uses the outbond seo links and Meta tags to get irrelevant traffic for their webpage.
3. Cloaking: In this we simply create two pages to cheat the Google, one for the SEO point of view another for the users. It comes under the advance black SEO techniques.
4. Internal linking with keyword anchor text: First of all I want to tell you that internal linking is not always
bad, Never Do excessive internal linking
5. Don't make a dedicated pages for keyword variant
6. Content Swapping