Also any business with embeddable products and SDKs. No one is happy to make their page heavier with a script they don't own. Fintech comes to mind. Analytics companies too.
Anything with complex dashboards. Anything tailored to power users - CRMs, help desk software.
Figure out your pitch too - your job may save server costs (and increase development costs but maybe don't mention that), optimize response time of employees, increase productivity, or retain shoppers.