Off the top of my head SS, Fallen One, Thor. He's used some kind of shield defense against all three. The main point though is that these so called top tiers have:-
a) great durability against energy attacks - you'd have to show Thanos demonstrating the energetic output to dispatch characters of this level of durability with ease.
b) superior speed and reflexes, you'd have to show Thanos (without his shields) showing the capability to counter the speed of characters with the cqc speed of Superman, BA, CM, even Orion.
He has no energy attacks potent enough to dispatch these guys in one or two hits, after all, these are characters that have withstood disintegration beams, tesseracts opening in their brains, novas, solar system attacks, Orion can erect his own energy shields even. Basically while he's tuffer than any single top tier here, he's not powerful enough to breeze past them with any kind of ease.
You seriously underestimate these guys if you think Thanos will just knock their heads together or back hand them, this would be a real fight. If they're putting all their effort into the struggle (using their speed) he won't even touch them more often than not.