Name few Black Hat SEO techniques?

[bellevoir]

Link Farming
Hidden text, etc.
Gateway or Doorway pages
Cloaking
Keyword Stuffing

 

[ShreyaKoushik23]

These are also few Black hat SEO techniques-
Cloaking, Link-exchanges, Duplicate Content, Buying Links, Keyword Stuffing, Hidden text, Link farms, Over-optimization.

 

[sadianisar]

Few of the Black Hat SEO techniques are:

Duplicate content
Keyword Stuffing
Reverse/Negative SEO
Google Bomb
Paid Back-links
Excessive back-links on the same keywords etc

 

[cheta]

buying fake traffic from software or bot to deceive Google to think it is real

 

[arsalan1101]

some of the blackhat techniques are as follow
keyword stuffing
content plagiarism
reverse/negative seo

 

[Jessicahoney]

There are Black hat seo techniques like doorway pages, keyword stuffing, hidden text, duplicate content, duplicate content on multiple sub domains, Cloaking.