Who are the righteous women?

Allah The Exalted Says (what means): {Perhaps his Lord, if he divorced you [all], would substitute for him wives better than you – Muslims, believing, devoutly obedient, repentant, worshipping, and touring [ones] -- previously married or virgins.} [Quran 66: 5]

Al-Qurtubi commented,

The meaning of "Muslims" is that they are sincere. This is the opinion of Sa‘eed ibn Jubayr . It was said that it means that they are submissive to the command of Allah The Almighty and the command of His Messenger, sallAllahu ‘alayhi wa sallam. They also believe in their commands and prohibitions, are obedient and are repentant of their sins, according to As-Suddi. It was said that the meaning of 'repentant ' is that they are adherent to the command of the Messenger of Allah, sallAllahu ‘alayhi wa sallam, and abandon their personal inclinations. They also worship Allah The Almighty intensely.

Ibn ‘Abbas, may Allah be pleased with him said,
‘Whenever worship is mentioned in the Quran, it refers to Tawheed (Islamic monotheism).’ As for 'touring', it means fasting, according to Ibn ‘Abbaas, Al-Hasan and Ibn Jubayr, may Allah be pleased with them. Zayd ibn Aslam and his son, ‘Abdul-Rahmaan are of the view that it means emigrants. Zayd said, ‘There is no tourism in the Ummah (nation) of Muhammad, sallAllahu ‘alayhi wa sallam, except for migration.’ Some of these women are previously married and others were virgins.

Allah The Exalted Says (what means): {So righteous women are devoutly obedient, guarding in [the husband's] absence what Allah Would Have them guard.} [Quran 4: 34]
Ibn Jareer said,

‘Abdullaah ibn Al-Mubaarak, may Allah be pleased with him, said, "I heard Sufyaan saying, 'Righteous women do good deeds.' Such women are obedient to Allah as well as their husbands. When their husbands are away from them, they safeguard themselves with regard their honor and property, as well as other rights that are due to Allah.”
Commenting on (guarding in [the husband's] absence) , Qataadah said, “They guard the duties that Allah has entrusted them with, and also guard the husbands' absence.” Commenting on (guarding in [the husband's] absence what Allah would have them guard) , As-Suddi said, “The woman guards her husband's property as well as her chastity until he returns, just as Allah has commanded her.” It was narrated on the authority of Ibn Jurayj that he said, “I asked ‘Ataa’ about the meaning of this, and he replied, ‘They guard their husbands’”
It was narrated on the authority of Abu Hurayrah that the Messenger of Allah, sallAllahu ‘alayhi wa sallam, said: "The best woman is she who pleases you when you look at her, obeys you when you command her and guards herself and your property when you are absent." Then, the Messenger of Allah, sallAllahu ‘alayhi wa sallam, recited the verse in which Allah The Exalted Says (what means): {Men are in charge of women…} [Quran 4: 34]

Abu Ja‘far said, “This prophetic Hadeeth stands as evidence that our interpretation is sound. It means that they are religiously righteous, obedient to their husbands, guarding themselves and their husbands' property.”

Al-Qurtubi said, "The verse in which Allah The Exalted Says (what means): {So righteous women are devoutly obedient, guarding in [the husband's] absence what Allah would have them guard}, all this is a statement and it implies a command that the woman is required to obey her husband and fulfill his right with regard to his property as well as herself when he is absent.”

A similar interpretation of the verse is mentioned in Tafseer Al-Jalaalayn.

In Faydh Al-Qadeer, Al-Munaawi said, "The beautiful, chaste and religious woman is the best treasure and saving her is better than saving gold and silver. Al-Qaadhi said, ‘A righteous woman is more beneficial than gold, because gold is only beneficial when it is given out. A righteous woman, however, as long as she is with you, pleases you when you look at her, satisfies your sexual desire, you consult her about what bothers you and she keeps your secrets and helps you fulfill your needs, and she obeys your command. When you are away, she guards your property and takes care of your children. If she only safeguards your honor and brings up your progeny, this would be enough to indicate her virtue.’"