I'm using NecroBot for this, but any PokemonGo Rocket API bots should work.
In Visual Studio, go to PokemonGo.RocketAPI.Logic and open Logic.cs
At line 147 it should say "var highestsPokemonPerfect = await _inventory.GetHighestPerfect(10);
Change the number 10 to any number you'd like (i.e: I have 30 to show the top 30 IV's).
Start the bot up, let it show all the percentages and stop it (by pressing enter).