The fiscal year for many businesses are ending soon which means budgets and taxes are on their minds. Now is a good time to have any end of the year sales or reach out to B2B buyers.
Sending custom one-off emails might be all you need to catch their attention. Especially if you have large buyers that you know about.
You can also use Repeat Customer Insights to see which customers have ordered the most. Either in terms of number of orders or amount spent. Then it's easy to export those email addresses for sending.