That's 7 cards. One of the Brigades is created.
So can NR. As a funny thought experiment, if all the stars align, you can pull 26 cards with one combo:
Syanna ready, then
Roche [1] + Roach [2]
|=> Fables [3] > Epidemic [4] kills Roche
|=> Blue Dream [5] on Roche
..........................................|=> Sile [6] on Roche
..........................................|=> HG Sword [7] on Roche
.................................................................................|=> D-Bomb [8] on Sword
.................................................................................|=> Regis [9] on Roche
|=> Caretaker [10] on Sword on Roche
...........................................................|=> Royal Decree [11] > Witchers x3 [12] [13] [14]
...........................................................|=> Last Wish [15] > Marching Orders [16] > Avallac'h [17] > Portal [18] > units x2 [19] [20]
|=> Villem [21] > Double-Cross [22] > Dandelion [23] > Shupe: Hunter [24] > John [25] > Winch [26]
This is excluding create effects, which could technically go infinite.
PS. The combo above is obviously not possible. It's just a thought experiment.
I dont know what you are, dedication incarnate or pure genius. But one thing is for certain. I would appreciate if you were on Gwent-design/philosophy team, as you always seem to contribute to new ideas and thoughts. Secondly, you are active both on the forums and in the game itself, hence your have basic understanding of the mechanics and the players feeling of/towards the game, by playing it yourself. I see you as the golden asset of this community and a future creative-design manager of Gwent. I hope that you go for it, as most of this community would appreciate to see you in that position.