Just to be clear, we're talking Thanos with the full power of the Infinity Gauntlet at his disposal. My plan is to compile a list of five individuals who can counteract the effects of the specific Infinity Stones. So without further ado...
Sentry's seemingly limitless power would surely be enough to counteract, or at least contain, the effects of the Power Stone.
2. Silver Surfer
The Silver Surfer's command over the Power Cosmic would be more than adequate to render the Space Stone useless.
Given that he is an android, and the fact that he himself has wielded the Mind Stone, means that he could potentially be immune to its effects.
4. Scarlet Witch
Wanda's control over the mind and reality make her the perfect candidate to go up against the Reality Stone.
Kitty Pride has the ability to transport the mind into another time, therefore being able to instantly counteract the Time Stone.