Pixiv fanart ranking by generation:

3: May > Steven >>>>>>>>>>>>>>>>> Brendan
4: Dawn > Cynthia >>>>>>>>>> Lucas
5: Battle Subway Twins >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> N > Hilda
6: Serena >>>>>>>>>>>>>>>>>>>>>>>>> Sycamore > Lysandre (Lillie and Chicken already have more fanart than anyone from gen 6 other than Serena)
7: Lillie >>>> Chicken >>>>>>>>>>> Lana