Praise be to Allaah.
May Allaah reward you with good for this concern and eagerness to do good and righteous deeds during this blessed month.
To the good deeds that you have mentioned may be added charity, feeding the poor, going for ‘Umrah and observing i’tikaaf for those who are able to do so.
As for the words that you can repeat whilst you are working, these include tasbeeh (saying Subhaan Allaah(Glory be to Allaah)), tahleel (saying Laa ilaaha ill-Allaah (There is no god but Allaah)), takbeer (saying Allaahu akbar (Allaah is most Great)), praying for forgiveness, making du’aa’ and responding to the muezzin. Keep your tongue moist with the remembrance of Allaah and seek a great reward with a few words which you can utter. For every tasbeehah you will have (the reward of) one charity, for every tahmeedah (saying Alhamdulillah (Praise be to Allaah)) you will have (the reward of) one charity, for every takbeerah you will have (the reward of) one charity, and for every tahleelah you will have (the reward of) one charity.
The Prophet (peace and blessings of Allaah be upon him) said: “Every person’s every joint must perform a charity every day the sun comes up, every tasbeehah is a charity, every tahmeedah is a charity, every tahleelah is a charity, every takbeerah is a charity, enjoining what is good is a charity, forbidding what is evil is a charity, and if you do two rak’ahs at duha time (the forenoon), that may be sufficient.” Narrated by Muslim, 720.
And he (peace and blessings of Allaah be upon him) said: “Two words which are light on the tongue and heavy in the Balance, and beloved to the Most Merciful: Subhaana Allaah wa bihamdih, subhaan Allaah il-‘Azeem (Glory and praise be to Allaah, glory be to Allaah the Almighty).” Narrated by al-Bukhaari, 6682; Muslim, 2694.
And he (peace and blessings of Allaah be upon him) said: “Whoever says ‘Subhaan Allaah il-‘Azeem wa bi hamdih (Glory and praise be to Allaah the Almighty),’ a palm tree will be planted for him in Paradise.” Narrated by al-Tirmidhi, 3465; classed as saheeh by al-Albaani in Saheeh al-Tirmidhi.
And he (peace and blessings of Allaah be upon him) said: “Whoever says ‘Astaghfir Allaah ul-‘azeem alladhi laa ilaaha illa huwa al-hayy ul-qayyoom wa atoobu ilayh (I seek the forgiveness of Allaah the Almighty, beside Whom there is no other god, and I repent to Him),’ will be forgiven even if he fled from the battlefield.” Narrated by Abu Dawood, 1517; al-Tirmidhi, 3277’ classed as saheeh by al-Albaani in Saheeh Abi Dawood.
And he (peace and blessings of Allaah be upon him) said: “There is no Muslim on earth who prays to Allaah for something but Allaah will grant him it, or divert an equivalent evil from him, so long as he does not pray for sin or the severing of family ties.” A man among the people said: “Then we will pray a great deal.” He said: “Allaah is most generous.” Narrated by al-Tirmidhi, 3573; classed as saheeh by al-Albaani in Saheeh al-Tirmidhi.
And he (peace and blessings of Allaah be upon him) said: “When you hear the muezzin, say what he says, then send blessings upon me, for whoever send one blessing upon me, Allaah will send ten blessings upon him. Then ask Allaah to grant me al-waseelah, which is a position in Paradise which will be attained by only one of the slaves of Allaah, and I hope that I will be the one. Whoever asks for al-waseelah for me, intercession will be granted for him.” Narrated by Muslim, 384.
And he (peace and blessings of Allaah be upon him) said: “Whoever says when he hears the call to prayer, ‘Allaahumma rabba hadhhi’l-da’wat il-taammah wa’l-salaat il-qaa’imah, aati Muhammadan al-waseelah wa’l-fadeelah wab’athhu maqaaman mahmoodan alladhi wa’adtahu (O Allaah, Lord of this perfect call and the prayer which is about to begin, grant Muhammad al-waseelah (a station in Paradise) and al-fadeelah (a rank above the rest of creation), and raise him to the praised position that You have promised),’ my intercession will be granted for him on the Day of Resurrection.” Narrated by al-Bukhaari, 614.
See also the answer to question no. 4156
May Allaah increase us and you in beneficial knowledge and righteous deeds.
And Allaah knows best.