For $3k spending in 90 days:
1. Bank of America Premium Rewards. Bonus: 50,000 points, redeemable for $500 credit. Annual fee of $95 not waived the first year.
2. CapitalOne Venture. Bonus: 50,000 points, redeemable for $500 travel credit. Annual fee of $95 waived the first year.
The reason to possibly get the Chase Sapphire Preferred first, though, is because of their 5/24 rule: if you open 5 or more credit card accounts in the last 24mo, you'll be declined. To meet the $4k spend, you could do something like buy gift cards for your future regular spending (Amazon, Target, etc).