Question Summary:
Can you enumerate the 73 sects with their beliefs?

Question Detail:

 
From various resources, we know that, Muslims will be divided into 73 firqahs and among them, only one will be the righteous one. ahle sunnah wal jalaah. 
There is a short interpretations of some of these aqeedahs in a book claimed to be written by Abdul Qader Jilani ( Rh). However, the list is incomplete and the descriptions are also very brief.
Since we are living in a time of fitnah, we need to know these aqeedahs properly to remain cautious of them. Could you please enumerate those 73 firqahs with vivid descriptions. Also please let us know the books/treatise where we can get those information at length.

Answer :

In the Name of Allah, the Most Gracious, the Most Merciful.
As-salāmu ‘alaykum wa-rahmatullāhi wa-barakātuh.
The Ulama' have compiled a number of books in an effort to identify the the names of the 72 deviated milal (sects). However, we should keep in mind that the names of the main, known sects are few in number. On the other hand, if one were to count all the sub-divisions of these well-known sects it might well add up to be more than 72.
There are a number of reasons for this:
1.) Some of the sub-divisions might have beliefs that take them out of the fold of Islam. As a result they would not be counted among the 72 deviated groups, because they would no longer be a sect, but disbelievers instead. As an example if, Allah forbid, somebody believes in the divinity of Ali (radiyallahu anhu) they would have left the fold of Islam.
2.) Rasulullah (salallahu alayhi wa sallam) did not say that these sects would all appear at one time. Some sects might appear in the future which would increase the number.
3.) Some sects although appearing to be separate or different might have the same usool (principles), thus being one sect in principle. As a result the number would vary depending on how they are identified. [i]
Keeping the above principles in mind we can be sure that the number of deviated sects is 72 because Rasulullah (salallahu alayhi wa sallam) has informed us.
Here is an example of how the 72 milal have been divided by the author of Mazahir Haqq [ii]:
The 72 milal plus (Ahl al-Sunnah Wal Jama'ah) for a total of 73 can be divided into 8 main groups:

Denomination

# of Sub-divisions

Beliefs

Mu'tazilah

20

Among their beliefs is that is that:

*One will not be able to see Allah on the Day of Judgement. 

*It is obligatory on Allah to reward the righteous and punish the disobedient.

*A believer who commits a major sin does not remain a believer and neither does he come a disbeliever – but occupies a position in between.

Shia

22

They give preference to Ali (radiyallahu anhu) over Abu Bakr, Umar and Uthman (radiyallahu anhum). Depending on the sect, some believe that the Quran is not present in its complete form and other beliefs that are not in conformity with the views of Ahl as Sunnah wal Jama'aah.  

Khawarij

20

*They initially supported Ali (radiyallahu anhu) but later opposed him.

*They believe that a person becomes a disbeliever after committing a major sin.

Murjiyah

5

They believe that only imaan (faith) in Allah is sufficient and one is not obligated to do any good deeds. Further, they believe that just as a disbeliever does not benefit from his good deeds, likewise a believer is not affected negatively by any of his bad deeds.

Najariyah

3

They reject the attributes of Allah.

Jabariyah

1

Their belief is that a person has no control or say over his actions.

Mushabiha

1

Their belief is that Allah has body parts like humans based on their literal assumptions. 

Najiyah

1

*This is the saved denomination, Ahl as Sunnah wal Jama'aah who are staunch followers of the sunnah of Rasulullah (salallahu alayhi wa sallam), respect and honor the Ahl al-bayt [family of Rasulullalllah (salallahu alayhi wa sallam)] and believe that all the Sahabah (radiyallahu anhum) are just and pious without exception.

*Abu Bakr (radiyallahu anhu) is the highest-ranking companion, then Umar, then Uthman and then Ali (radiyallahu anhum).