Korean Air has the absolute best first class award availability. Most Korean flights will feature at least 2 first class award seats, but 3 and 4 is common on some routes. They offer great value Europe business class awards on partners and Hawaii awards on partners.
They also have one of the most generous policies that lets you put an award on hold without the points yet in your account. That gives you time to transfer points in from a credit card partner after you’ve already secured the award.