My list of big Nintendo IP's based on sales average: (rough estimate)
20-25 million potential: Mario, Open Sky Zelda
15-20 million potential: Mario Kart
10-15 million: Animal Crossing, Smash Bros, Pokémon
5-10 million potential: Donkey Kong, Kirby, Luigi's Mansion, Zelda, Splatoon
1-5 million potential: Xenoblade, Metroid, Fire Emblem, Yoshi
I was creating my own list based on feeling first but then decided to look at overall sales data and take averages from that. Then out of nowhere you see how crazy the Switch has pushed some franchises and the feel of those franchises as well. You would think that Animal Crossing, Splatoon, Zelda are all powerhouses but overall they only became one during the Switch time. I did take the Open Sky Zelda games as something separate as they are powerhouses on their own just to show the big difference. Pokémon is deemed big but in the end it is on a similar level of Animal Crossing and Smash Bros. Albeit on the border as Pokémon was reaching around 14,72 million average sales approx.
Just interesting to see when you put some rough data and average it.