Haven't posted here in a very long time, but this list is missing a ton of guys. It appears to come from sports-reference.com, but the site doesn't seem to mention the criteria used (minimum attempts per game? minimum per career?). From the same site, just trying some names, I get:
Kent McCausland ballin' out at 45.3%
BJ Armstrong 44.3% (3 yrs with the 3pt line)
Josh Dix 41.9% (3 yrs)
Joe Wieskamp 41.2% (3 yrs)
Luke Recker 41.9% in 2 yrs at Iowa (39.4% total)
Peter Jok 37.8%
Keegan Murray 37.3% (2 yrs)
Matt Gatens 36.7% (also has the 4th most career 3pt attempts at Iowa so I don't know how he doesn't qualify for their percentage list)
Luka Garza 36.7%
Andre Woolridge 38.0% at Iowa (37.1% total)
Jarrod Uthoff 38.3% (3 yrs)
Brock Harding 39.1% (2 yrs)
Troy Skinner 38.9%
Jeff Moe 41.7% (2 yrs with the 3pt line)
Dean Oliver 36.8%
Nicholas Baer 37.3%
Jim Bartels 37.3%
Devan Bawinkel 37.2% in 2 yrs at Iowa, 36.1% total
Jake Kelly 39.0% at Iowa (36.1% total)
Justin Johnson 37.5% (2 yrs)
Anthony Tucker 36.8% (2 yrs)
Ryan Luehrsmann 36.4%
JR Koch 36.8%
Pryce Sandfort 38.6% (2 yrs)
CJ Fredrick 46.6% in 2 yrs at Iowa, 41.2% overall
Isaiah Moss 39.1% in 3 yrs at Iowa, 37.8% overall
Jess Settles even sneaks into the list at 35.2%