We use Blackwing 602’s in every office. Nothing else comes close. Yes, they are expensive, but they are a joy to use. The line is as black as a 3B and the lead as hard as a 3H with hardly any drag. As a bonus, the (replaceable) rubber that the pencil comes equipped with works brilliantly.
https://www.amazon.com/Palomino-Blackwing-Pencils-12-Count/dp/B006CQWILK

