Brex
Brex is a corporate card that requires no personal guarantee (meaning it isn't impacted and doesn't impact your personal credit. They provide uncapped travel and rewards points and claim to offer higher credit limits than Amex or other cards.
American Express Business Card
AMEX is the classic business credit card. It's only $50 per card per year, so you won't break the bank. They provide excellent support, along with unique perks.
Ramp
Ramp in a new corporate card company (and Brex competitor) that is built for startups and gives you 1.5% cash back on everything as opposed to being points based. They also offer no founder liability and higher credit limits and focus a lot more on savings than competitors.