There are two credit cards with large sign-up bonuses that are set to expire this week.

The CitiBusiness/AAdvantage Platinum Select World MasterCard: 70,000 bonus American Airlines miles for spending $4,000 on the new card within three months of account opening. You must apply by today (October 9, 2018) to qualify for this bonus offer. 
The Citi ThankYou Premier: 60,000 bonus ThankYou Points for spending $4,000 on the new card within three months of account opening.