Repeating the name of Allaah on its own, or the pronoun “Huwa” (He), is a Sufi bid’ah
Question

                Is there any harm in repeating the names of Allah SWT?
As zikr, or anything else?
I understand saying "Astagh firullah" or "Subhan Allah" or "Alhamdo Lillah" are ok...
Praise be to Allah.There is no doubt that it is bid’ah to mention the name of Allaah on its own or –even worse – to repeat the pronoun “Huwa” (“He”). Shaykh al-Islam Ibn Taymiyah (may Allaah have mercy on him) said:
The Name of Allaah on its own, either as a noun (“Allaah”) or a pronoun (“Huwa”) is not a complete phrase or meaningful sentence. It has no implications to do with eemaan (faith) or kufr (disbelief), commands or prohibitions. This was not mentioned by anyone from the Salaf (early generations) of this ummah, and it was not prescribed by the Messenger of Allaah (peace and blessings of Allaah be upon him). It does not bring any knowledge to the heart or bestow any kind of benefit upon it. All it does is give an unclear idea which is not defined by any negation or affirmation. Unless there is previous knowledge in a person's mind or he is in a state of mind where he could benefit from this, he gains no benefit at all. Islam prescribes adhkaar which in and of themselves bring benefit to the heart, without any such need for anything else.
Some of those who persisted in this kind of “dhikr” ended up in various kinds of heresies and ideas of “wahdat al-wujood” (unity of all that exists, pantheism), as has been explained in detail elsewhere.
It was mentioned that one of the shaykhs said: “I am afraid of dying between negation and affirmation”, but this is not an example to be followed, because it is obviously erroneous. If a person were to die in this state, he would die according to his intention, because actions are judged by intention. It was reported that the Prophet (peace and blessings of Allaah be upon him) commanded us to tell the dying person to say Laa ilaaha ill-Allaah,and he said, “Anyone whose last words are Laa ilaaha ill-Allaah will enter Paradise.” If this word (Laa ilaaha ill-Allaah) was something which required caution, why should we tell the dying person to say something which, if he dies in the middle of saying it, will lead to an improper death? Rather, if this were the case, he would be told to say “Allaah, Allaah” or “Huwa, Huwa.” 
Mentioning the pronoun on its own is further removed from the Sunnah and is a worse kind of bid’ah, which is closer to the misguidance of the Shaytaan. If a person says “Yaa Huwa, yaa Huwaa (O He, O He)” or “Huwa, Huwa (He, He)” and so on, the pronoun does not refer to anything except whatever his heart imagines, and hearts may be guided or misguided.
Some shaykhs use as evidence to support saying “Allaah” (the name on its own) the aayah (interpretation of the meaning):
“Say: ‘Allaah.’ Then leave them…” [al-An’aam 6:91]. They think that Allaah commanded His Prophet to say His Name on its own, but this is a mistake according to the consensus of the scholars, because the meaning of the phrase “Say ‘Allaah’” is that it is Allaah Who sent down the Book which was brought by Moosa. This is in response to the question:
“Say (O Muhammad): ‘Who then sent down the Book which Moosa (Moses) brought, a light and a guidance to mankind which you (the Jews) have made into (separate) paper sheets, disclosing (some of it) and concealing (much). And you (believers in Allaah and His Messenger Muhammad) were taught (through the Qur’aan) that which neither you nor your fathers knew.’ Say: ‘Allaah (sent it down).’” [al-An’aam 6:91 – interpretation of the meaning], i.e., Allaah is the One Who revealed the Book which was brought by Moosa. This is a refutation of the view of thosewho said, “Nothing did Allaah send down to any human being (by Revelation)”[al-An’aam 6:91 – interpretation of the meaning]. Allaah says: Who then sent down the Book which Moosa brought? Then He says: Say Allaah sent it down, then leave these liars to play in their vain discussions.
What we have said above is further explained by the comments of Seebawayh and other grammarians, who noted that when the Arabs say “Qaala” (or other forms of the verb meaning “to say”), they do not quote verbatim, rather they state what was said, giving a complete meaning. So what follows is a sentence with a complete meaning, or a nominal sentence or a verbal sentence. Hence after saying “qaala” they give a kasrah to the particle “anna” (making it “inna”); “qaala” cannot be followed by a noun standing alone. Allaah did not command anyone to mention His Name on its own, and it is not prescribed for the Muslims to say His Name on its own. Saying His Name on its own does not enhance faith or explain anything about the religion, according to the consensus of the scholars of Islam; it is not enjoined in any act of worship or in any case where Allaah addresses them.
(Majmoo’ al-Fataawa, 10/226-229)
 And he (may Allaah have mercy on him) also said:
 Repeating the Name of Allaah on its own, such as saying “Allaah, Allaah,” or the pronoun, such as “Huwa, Huwa” is not prescribed in either the Qur’aan or the Sunnah. It is not reported that any of the salaf of this ummah or any of the righteous scholars who are taken as examples did this. It is only spoken by misguided people of the later generations.
 Perhaps they are following a shaykh who had no control over himself in this regard, such as al-Shubli who, it was narrated, used to say ‘Allaah, Allaah.’ It was said to him, ‘Why do you not say Laa ilaaha ill-Allaah?’ He said, “I am afraid of dying between the negation [saying La ilaaha (there is no god)] and the affirmation [ill-Allaah (except Allaah)]”!
This is one of the mistakes made by al-Shubli, who may be forgiven for it because of the sincerity of his faith and the strength of his emotions which overwhelmed him. Sometimes he would go crazy and would be taken to the asylum, and he would shave off his beard. There are other instances of this type in his case, which are not to be taken as examples, even if he may be excused or rewarded for them. If a person intends to say Laa ilaaha ill-Allaah, and he dies before completing it, that will not harm him at all, because actions are judged by intentions, and what he intended to do is what will be written down for him.
Some of them go to extremes in this matter, and say that saying the name of Allaah is for the ‘elite’ whilst saying La ilaaha ill-Allaah is for the ‘masses.’ Some of them say that saying Laa ilaaha ill-Allaah is for the mu’mineen (believers), saying ‘Allaah’ is for the ‘aarifeen’ and saying ‘Huwa’ is for the muhaqqiqeen. One of them may restrict himself to saying, when alone or in a gathering, ‘Allaah, Allaah, Allaah’ or ‘Huwa’ or ‘Yaa Huwa’ or even ‘La Huwa illa Huwa (there is no He except He)’! Some of those who have written about spiritual matters have expressed approval of this, quoting some known figures who, however, were in a state of overwhelming emotion at the time, or quoting opinions, or quoting false reports – for example some of them reported that the Prophet (peace and blessings of Allaah be upon him) told ‘Ali ibn Abi Taalib to say ‘Allaah, Allaah, Allaah.’ The Prophet (peace and blessings of Allaah be upon him) said it three times, then he told ‘Ali to say it three times so he said it three times. This hadeeth is fabricated (mawdoo’), according to the consensus of the scholars of hadeeth.  
It is narrated that the Prophet (peace and blessings of Allaah be upon him) taught people various adhkaar to say, and the best of dhikr is Laa ilaaha ill-Allaah. This is what he urged his paternal uncle Abu Taalib to say when he was dying. He said, “O uncle, say Laa ilaaha ill-Allaah and I will defend you thereby before Allaah.” And he said: “I know of a word which no one says when he is dying but his soul finds rest in it.” And he said, “Anyone whose last words are Laa ilaaha ill-Allaah will enter Paradise.” And he said, “Whoever dies knowing that there is no god except Allaah will enter Paradise.” And he said: “I have been commanded to fight people until they bear witness that there is no god except Allaah and that Muhammad is the Messenger of Allaah. If they do that, their blood and wealth will be safe from me, except for what is due from them [e.g., zakaah etc.], and their reckoning is with Allaah.” And there are many similar ahaadeeth.
(Majmoo’ al-Fataawaa, 10/556-558)
Whoever makes the Qur’aan and Sunnah his points of reference concerning his worship will not fail to distinguish right from wrong. We ask Allaah to bring us back to His religion in a gentle manner. And Allaah knows best.