Imām al-Suyūṭī transmits from Ibn al-Jazarī that the types of recitation are six:
1. Mutawātir: This is [a recitation] that has been transmitted by such a large group that it is not possible that [ from the first to the last] they all agreed to lie. 
Example: Those recitations whose routes of transmission agree from among the seven. This is the case of majority of the recitations.
2. Mashhūr: It is that [recitation] whose chain of transmission is ṣaḥīḥ due to its narrators being upright and precise individuals who transmit from people of similar qualities who report from people of similar qualities [and so on until you reach back to the Prophet, may peace and blessings be upon him], it is consistent with the Arabic language, agrees with one of the Uthmanic Maṣāḥif (pl. of muṣḥaf) whether it be transmitted from the seven a’immah (pl. of imām) or the ten or others from among those a’immah that are accepted, it is well-known among the scholars of recitation (i.e. the Qurrā) and they don’t consider it to be incorrect nor do they consider it to be shādh, however it has not reached the level of mutawātir. 
Example: Recitations whose routes of transmission from the seven differ, so some narrators will transmit it while others will not.  
These two categories are such that they are recited; it is necessary to believe in them and it is impermissible to denying anything from them.
3. Āḥād: It is that [recitation whose] chain of narrators is ṣāḥīḥ, however it contradicts the rasm [.i.e that which was written in the maṣāḥif dispatched by Uthmān, may Allāh be pleased with him], or it contradicts the Arabic language, or it does not have the aforementioned renown [i.e. it not well-known among the scholars of recitation (i.e. the Qurrā)]. 
An example is what is [mentioned] by Ḥākim by way of ^cĀṣim al-Jaḥdarī on the authority of Abu Bakrah that the Prophet, may peace and blessing of Allāh be upon him, recited: (متكئين على رفارف خضر و عباقري حسان) [Ṣūrah al-Raḥmān, Āyah 79]. 
[Another example] is the recitation of (لقد جاءكم رسول من أنفَسِكم) [Ṣūrah Tawbah, Āyah 128] with a fatḥa on the fā.
4. Shādh: It is that [recitation whose] chain of narrators is not ṣaḥīḥ. 
For example, the recitation of Ibn al-Samyaf^ca: (فاليوم ننحيك ببدنك) with a dotless ḥa (لتكون لمن خلفك اية) with a fatḥa on the lām of the word (خلفك). [Ṣūrah Yūnus, Āyah 92]
5. Mawḍū^c: It is such recitation that is attributed to someone without any basis. 
Example: Those recitations that Muḥammad ibn Ja^cfar al-Khazā^cī attributed to [Imām] Abū Ḥanīfah. 
[Abū al-Faḍl Muḥammad ibn Ja^cfar al-Khuzā^cī collected them and it was transmitted from him by Abū al-Qāsim al-Hudhalī. Part of it is: (إنما يخشى الله من عباده العلماء) with (الله) in the nominative (i.e. read with a dhamma) and (العلماء) in the accusative (i.e. read with a fatḥa). Al-Dārqutnī and a group of scholars have written that this book is a fabrication that has no basis. (al-Itqān Fī ^cUlūm al-Qur’ān. Jalāluddīn al-Suyūṭī. Taḥqīq: Shu^cayb al-Arna’ūṭ. Muassas al-Risālah. p. 166)] 
6. Recitations that resemble the category of Mudraj in the [science] of Ḥadīth: It is an addition in the recitation in the form of exegesis. 
For example, the recitation of Sa^cd ibn Abī Waqqāṣ: (و له أخ أو أخت من أم) [Ṣūrah al-Nisā, Āyah 12] with the addition of the wording (من أم), the recitation of (ليس عليكم جناح أن تبتغوا فضلا من ربكم في مواسم الحج) [Ṣūrah Baqarah, Āyah 198], with the addition of the wording (في مواسم الحج), and the recitation of al-Zubayr: (ولتكن منكم أمة يدعون إلى الخير و يأمرون بالمعروف و ينهون عن المنكر و يستعينون بالله على ما أصابهم) [Ṣūrah Āli Imrān, Āyah 104] with the addition of the wording (و يستعينون بالله على ما أصابهم).
This is merely a resemblance and not actual mudraj, because there is a difference of opinion concerning it. Umar, may Allah be pleased with him, said, “I don’t know if it was his recitation (i.e. Zubayr’s recitation) or if he was giving exegesis.” Sa^cīd ibn Manṣūr extracted it, as well as Ibn al-Anbārī who was firm on it being exegesis.”
[Another example is] Ḥasan’s recitation: (وإن منكم ألا واردها الورود الدخول). Ibn al-Anbārī said, “His statement: (الورود الدخول) is exegesis on the part of Ḥasan for the meaning of (الورود). Some of the narrators made an error and inserted it into the Qur’ān.”
At the end Ibn al-Jazarī said, “It may sometimes happen that they inserted exegesis into the address for clarification because they were certain of what they had received from the Messenger of Allāh, may peace and blessings be upon him, in the form of Qur’ān, and thus they were safe from confusion and mixups.”
(Manāhil al-^cIrfān, Shaykh Muḥammad Abdul-^cAẓīm al-Zarqānī. Ṭaḥqīq: Fawwāz Aḥmad Zamaralī. Dār al-Kitāb al-^cArabī. 1:349-350)