List of All Top Level Domains (TLD)

The top level domains are the domain names which are in the root zone of the name space. Country Code Top Level Domains are in the Domain Name System with their two letter code. There are some internationalized country code top-level domains (IDN ccTLD) which retain their traditional ASCII-based ccTLDs. Generic top level domains (gTLD) has three or more characters.

Importance of understanding Top Level Domains (TLD)

Having own domain name : It is desirable to have Top Level Domains (TLD) for being a good performer in search engine result page, as believed by most SEO experts. The reason is, the ownership has been verified and the person (owner) is believed to be traceable. Backlinks from Generic top level domains (gTLD) has the highest value. Reserved means, the TLD is not open to public or need special permission to acquire.

List of Top Level Domains (TLD)

These Top Level Domains (TLD) can be openly purchased :

.com Generic top-level domain
.info Generic top-level domain
.net Generic top-level domain
.org Generic top-level domain

These Top Level Domains are available only to certain population :

.asia Restricted not reserved
.biz Restricted not reserved

Fully reserved, needs official documentation for ownership :

.aero Reserved
.ac. Reserved
.arpa Reserved
.cat Reserved
.coop Reserved
.edu Reserved
.gov Reserved
.int Special use, Reserved
.jobs Reserved
.mil Reserved
.mobi Reserved
.museum Reserved
.tel Reserved

Reserved, but claim can be done by an individual:

.name Reserved, can be claimed
.pro Restricted, can be claimed
.travel Reserved, can be claimed
.xxx Reserved, can be claimed

Note for All Top Level Domains (TLD) mentioned above

.gov is for US government only. Country level usage is like .gov.in (.in for India)
.ac was for Ascension Island (Population is around 880), now it stands for academia. Similarly, .ac.in (.in for India) is used to denote country.
.pro can be claimed by professionals like established performers, doctors, Lawyers etc. For doctors, there has been argument for a separate TLD (no progress so far).
.name can be registered by a real person.

I, for example can apply for .pro, .name and some special extension in future. Most general people can only apply for .name

I, however can not apply for .edu (or country level .edu.in) or .gov (or country level .edu.in)

So, All Top Level Domains available for me are :

.com Generic top-level domain
.info Generic top-level domain
.net Generic top-level domain
.org Generic top-level domain
.asia Restricted not reserved
.name Reserved, can be claimed
.pro Restricted, can be claimed

For example Mrs. Corrine residing in US, a non-professional, retired person, All Top Level Domains available are :

.com Generic top-level domain
.info Generic top-level domain
.net Generic top-level domain
.org Generic top-level domain
.name Reserved, can be claimed