Sahih Muslim 2848
Sahih Muslim · Book 53: The Book of Paradise, its Description, its Bounties and its Inhabitants · The Arrogant Will Enter The Fire, And The Humble Will Enter Paradise
Anas reported Allah's Apostle (ﷺ) as saying:
حَدَّثَنِي زُهَيْرُ بْنُ حَرْبٍ ، حَدَّثَنَا عَفَّانُ ، حَدَّثَنَا حَمَّادٌ، - يَعْنِي ابْنَ سَلَمَةَ - أَخْبَرَنَا ثَابِتٌ ، قَالَ سَمِعْتُ أَنسًا ، يَقُولُ عَنِ النَّبِيِّ صلى الله عليه وسلم قَالَ " يَبْقَى مِنَ الْجَنَّةِ مَا شَاءَ اللَّهُ أَنْ يَبْقَى ثُمَّ يُنْشِئُ اللَّهُ تَعَالَى لَهَا خَلْقًا مِمَّا يَشَاءُ " .
There would be left some space in Paradise as Allah would like that to be left. Then Allah would create another creation as He would like.