You can set up email alerts through Raise.com to send you an email whenever a new Target card is posted on their site. It's a bit annoying since its a lot of emails but it may help you jump on higher % off ones if you're able to keep an eye on your email throughout the day.
I signed up for TopCashBack yesterday, but noticed that it says they only give 1% back for certain cards purchased on Raise, and Target is one of those cards. They give 2% back on Cardpool purchases, no restrictions. I didn't look closely at either site to see if one has the Target cards at a higher % off than the other though.