Let's see, looking at Produce 101 and Produce 48, we have:
Choi Yena:
- Top charting song: Smiley at #8
- Total album sales: 567,380
- Best selling album: 139,421 for Smartphone
Kwon Eunbi:
- Top charting song: Underwater at #78
- Total album sales: 187,125
- Best selling album: 58,183 for Open
Lee Chaeyeon:
- Top charting song: Knock at #26
- Total album sales: 92,004
- Best selling album: 41,587 for Hush Rush
Jo Yuri:
- Top charting song: Love Shh! at #97
- Total album sales: 284,455
- Best selling album: 96,267 for Op.22 Y-Waltz : in Major
Chungha:
- Top charting song: Gotta Go and Snapping at #2
- Total album sales: 145,158
- Best selling album: 29,082 for Querencia
Kim Sejeong:
- Top charting song: Flower Way at #2
- Total album sales: 45,520
- Best selling album: 27,491 for Door
Somi:
- Top charting song: Fast Forward at #5
- Total album sales: 124,712
- Best selling album: 65,779 for Game Plan
Used wiki for charting and koreansalestwt.blogspot.com for sales.
So arguably, Chungha on top in terms of song charting and Yena for sales. Yena's worst selling album (at 77,376) is still above everyone but Yuri's best selling album.