Some of the basic ones are:
cloaking
keyword stuffing
doorway pages
Scrapping
I gathered some info which might be useful too 
Cloaking is a black hat search engine optimization (SEO) technique in which the content presented to the search engine spider is different from that presented to the users' browser. This is done by delivering content based on the IP addresses or the User-Agent HTTP header of the user requesting the page. When a user is identified as a search engine spider, a server-side script delivers a different version of the web page, one that contains content not present on the visible page. The purpose of cloaking is to deceive search engines so they display the page when it would not otherwise be displayed.
The only legitimate uses for cloaking used to be for delivering content to users that search engines couldn't parse, like Adobe Flash. As of 2006, better methods of accessibility, including progressive enhancement are available, so cloaking is not necessary. Cloaking is often used as a spamdexing technique, to try to trick search engines into giving the relevant site a higher ranking; it can also be used to trick search engine users into visiting a site based on the search engine description which site turns out to have substantially different, or even pornographic content. For this reason, major search engines consider cloaking for deception to be a violation of their guidelines, and therefore, they delist sites when deceptive cloaking is reported.[1][2][3][4][5]
Cloaking is a form of the doorway page technique.
A similar technique is also used on the Open Directory Project web directory. It differs in several ways from search engine cloaking:
- It is intended to fool human editors, rather than computer search engine spiders.
- The decision to cloak or not is based upon the HTTP referrer, the user agent or the visitor's IP. The referrer tells the URL of the page on which a user clicked a link to get to the page. Some cloakers will give the fake page to anyone who comes from a web directory website, since directory editors will usually examine sites by clicking on links that appear on a directory web page. Other cloakers give the fake page to everyone except those coming from a major search engine; this makes it harder to detect cloaking, while not costing them many visitors, since most people find websites by using a search engine.
Cloaking versus IP Delivery
Cloaking can be a form of IP delivery, where different content is served based upon the requester's IP address. With cloaking, search engines and people never see the other's pages, whereas, with other uses of IP delivery, both search engines and people can see the same pages.
One use of IP delivery is to determine the requestor's location, and deliver content specifically written for that country or language. IP delivery isn't necessarily cloaking. For instance, Google uses IP delivery for AdWords and AdSense advertising programs in order to target users in different geographic locations, or users who have their browser set for different natural languages.
As of 2006, many well-known and well respected sites have taken up IP delivery to personalise content for their regular customers. In fact, many of the top 1000 sites, including household names like Amazon (amazon.com), actively use IP delivery. None of these have been banned from search engines because their intention is not deceptive.