Sha'ban was the month most fasted by the Prophet ﷺ outside of Ramadan

The Prophet ﷺ never fasted in any month more than in the month of Sha'ban.

He used to say, "Do those deeds which you can do easily, as Allah will not get tired (of giving rewards) till you get bored and tired (of performing religious deeds)." The most beloved prayer to the Prophet ﷺ was the one that was done regularly (throughout the life) even if it were little. And whenever the Prophet ﷺ offered a prayer he used to offer it regularly.  

لَمْ يَكُنِ النَّبِيُّ ﷺ يَصُومُ شَهْرًا أَكْثَرَ مِنْ شَعْبَانَ فَإِنَّهُ كَانَ يَصُومُ شَعْبَانَ كُلَّهُ

وَكَانَ يَقُولُ خُذُوا مِنَ الْعَمَلِ مَا تُطِيقُونَ فَإِنَّ اللَّهَ لاَ يَمَلُّ حَتَّى تَمَلُّوا وَأَحَبُّ الصَّلاَةِ إِلَى النَّبِيِّ ﷺ مَا دُووِمَ عَلَيْهِ وَإِنْ قَلَّتْ وَكَانَ إِذَا صَلَّى صَلاَةً دَاوَمَ عَلَيْهَا  

The Messenger of Allah ﷺ did not observe fast in any month of the year more than in the month of Sha'ban, and used to say: Do as many deeds as you are capable of doing, for Allah will not become weary (of giving you reward), but you would be tired (of doing good deeds) ; and he also said: The deed liked most by Allah is one to which the doer adheres constantly even if it is small.  

لَمْ يَكُنْ رَسُولُ اللَّهِ ﷺ فِي الشَّهْرِ مِنَ السَّنَةِ أَكْثَرَ صِيَامًا مِنْهُ فِي شَعْبَانَ وَكَانَ يَقُولُ خُذُوا مِنَ الأَعْمَالِ مَا تُطِيقُونَ فَإِنَّ اللَّهَ لَنْ يَمَلَّ حَتَّى تَمَلُّوا وَكَانَ يَقُولُ أَحَبُّ الْعَمَلِ إِلَى اللَّهِ مَا دَاوَمَ عَلَيْهِ صَاحِبُهُ وَإِنْ قَلَّ  

[Machine] Aisha, the wife of the Prophet ﷺ, said that he did not fast more in any year than he did in the month of Sha'ban. He would fast the entire month of Sha'ban and would say, "Take on only what you are able to handle in terms of deeds, for Allah does not tire until you tire. The deeds that were most beloved to the Prophet ﷺ were those that were done consistently, even if they were few in number. And when he would perform a prayer, he would consistently perform it."  

عَائِشَةُ لَمْ يَكُنْ رَسُولُ اللهِ ﷺ يَصُومُ مِنَ السَّنَةِ أَكْثَرَ مِنْ صِيَامِهِ مِنْ شَعْبَانَ فَإِنَّهُ كَانَ يَصُومُ شَعْبَانَ كُلَّهُ وَكَانَ يَقُولُ خُذُوا مِنَ الْعَمَلِ مَا تُطِيقُونَ فَإِنَّ اللهَ لَا يَمَلُّ حَتَّى تَمَلُّوا وَإِنَّهُ كَانَ أَحَبُّ الْأَعْمَالِ إِلَى رَسُولِ اللهِ ﷺ مَا دَاوَمَ عَلَيْهَا وَإِنْ قَلَّتْ وَكَانَ إِذَا صَلَّى صَلَاةً دَاوَمَ عَلَيْهَا  

[Machine] The Prophet ﷺ used to fast from the months of the year more in the month of Sha'ban. He used to fast the whole month of Sha'ban and he used to say, "Take from actions what you are capable of, for Allah does not get tired until you get tired." Indeed, prayer was most beloved to him when he consistently performed it, even if it was little. And whenever he prayed a certain prayer, he would continue to pray it consistently.  

أَنَّ النَّبِيَّ ﷺ لَمْ يَكُنْ يَصُومُ مِنْ شَهْرٍ مِنَ السَّنَةِ أَكْثَرَ مِنْ صِيَامِهِ مِنْ شَعْبَانَ فَإِنَّهُ كَانَ يَصُومُ شَعْبَانَ كُلَّهُ وَكَانَ يَقُولُ خُذُوا مِنَ الْعَمَلِ مَا تُطِيقُونَ فَإِنَّ اللهَ ﷻ لَا يَمَلُّ حَتَّى تَمَلُّوا فَإِنَّهُ كَانَ أَحَبُّ الصَّلَاةِ إِلَيْهِ مَا دَاوَمَ عَلَيْهَا وَإِنْ قَلَّ وَكَانَ إِذَا صَلَّى صَلَاةً يُدَاوِمُ عَلَيْهَا  

[Machine] It was reported that the Prophet ﷺ did not fast more in any month of the year than he did in Sha'ban. He used to fast the entire month of Sha'ban. He used to say, "Take from your actions what you can bear, for Allah does not tire until you tire. The most beloved prayer to the Messenger of Allah ﷺ was the one that was consistent, even if it was little." When he would pray a prayer, he would remain consistent in it.  

أَنَّ النَّبِيَّ ﷺ لَمْ يَكُنْ يَصُومُ مِنْ شَهْرٍ مِنَ السَّنَةِ أَكْثَرَ مِنْ صَوْمِهِ مِنْ شَعْبَانَ فَإِنَّهُ كَانَ يَصُومُ شَعْبَانَ كُلَّهُ وَكَانَ يَقُولُ خُذُوا مِنَ الْعَمَلِ مَا تُطِيقُونَ فَإِنَّ اللهَ ﷻ لَا يَمَلُّ حَتَّى تَمَلُّوا وَإِنَّهُ كَانَ أَحَبُّ الصَّلَاةِ إِلَى رَسُولِ اللهِ ﷺ مَا دُووِمَ عَلَيْهَا وَكَانَ إِذَا صَلَّى صَلَاةً دَاوَمَ عَلَيْهَا