I know the similar surahs that the Messenger of Allah ﷺ used to recite, twenty surahs in ten rak'ahs." Then he took 'Alqamah's hand and went in, then 'Alqamah came out and we asked him and he told us what they were. (Using translation from Nasāʾī 1004)  

«إِنِّي لَأَعْرِفُ النَّظَائِرَ الَّتِي كَانَ يَقْرَأُ بِهِنَّ رَسُولُ اللهِ ﷺ عِشْرِينَ سُورَةً فِي عَشْرِ رَكَعَاتٍ ثُمَّ أَخَذَ بَيْدِ عَلْقَمَةَ فَدَخَلَ ثُمَّ خَرَجَ إِلَيْنَا عَلْقَمَةُ فَسَأَلْنَاهُ فَأَخْبَرَنَا بِهِنَّ»  

A man came to Ibn Masʿud and said, "I recited the Mufassal (Suras) at night in one rakʿa." Ibn Masʿud said, "This recitation is (too quick) like the recitation of poetry. I know the identical Suras which the Prophet ﷺ used to recite in pairs." Ibn Masʿud then mentioned 20 Mufassal Suras including two Suras from the family of (i.e. those verses which begin with) Ha, Meem [??] (which the Prophet ﷺ used to recite) in each rakʿa. (Using translation from Bukhārī 775)  

«هَذًا كَهَذِّ الشِّعْرِ؟ لَقَدْ عَرَفْتُ النَّظَائِرَ الَّتِي كَانَ رَسُولُ اللهِ ﷺ يَقْرِنُ بَيْنَهُنَّ فَذَكَرَ عِشْرِينَ سُورَةً مِنَ الْمُفَصَّلِ سُورَتَيْنِ سُورَتَيْنِ فِي كُلِّ رَكْعَةً»  

[Machine] "This is like this poetry, but the Messenger of Allah ﷺ used to recite the equivalent of twenty Surahs from the Mufassal and the Alif Lam Meem family."  

«هَذًّا كَهَذِّ الشِّعْرِ؟ لَكِنَّ رَسُولَ اللهِ ﷺ كَانَ» يَقْرَأُ النَّظَائِرَ عِشْرِينَ سُورَةً مِنَ الْمُفَصَّلِ وَآلِ حم