If by “New Black Hat SEO Techniques” you mean tactics designed to manipulate search rankings rather than improve the actual value of a website, they can include practices such as scaled low-quality content, link spam, misleading redirects, hidden content, and attempts to manipulate user or search-engine signals.
These methods may sometimes produce short-term ranking changes, but they carry significant risks, including ranking drops, loss of visibility, manual actions, and damage to a website’s reputation. Search engines continuously improve their systems to identify manipulative patterns.
For sustainable SEO, it is generally better to focus on helpful original content, strong technical SEO, relevant keywords, genuine backlinks, good website experience, and content that directly satisfies the user's search intent.