Q:

Who is the scientist referenced in Thor that had all his stuff taken by SHIELD?

I’m rewatching Thor, and I wondered if any reference is made in Ant-Man or another movie to the scientist that had all his stuff taken by SHIELD? This comment happens right after all Jane’s equipment is taken by  Coulson maybe 50 minutes into the first Thor movie.

SELVIG
            No one knows much about them. But
            I knew a scientist -- a pioneer in
            gamma radiation. SHIELD showed up,
            and he was never heard from again.

I was thinking it could have been Hank Pym, but I’m not that familiar with the timelines and when he started with SHIELD. Or like, how old Erik Selvig is supposed to be. It’s strange they never did anything with this, considering all the time ins between the movies, but maybe it was just a passing comment - or a plot line that never came together?

A:

I’ve always believed it to be Bruce Banner as chronologically it’s the one that makes sense.
This is heavily implied during the events of The Avengers when Black Widow states “we never lost you” as the answer to Bruce’s question “are you following me”.
Additionally Bruce Banner is regarded as the biggest expert in gamma radiation in the MCU so that aligns with the comment by Selvig:

I knew a scientist -- a pioneer in gamma radiation. SHIELD showed up, and he was never heard from again.

A:

This is almost certainly a reference to Bruce Banner as he is an expert in gamma radiation.

Bruce Banner: What does Fury want me to do? Swallow it?
Natasha Romonaff: Well, he wants you to find it. It's been taken. It emits a gamma signature that's too weak for us to trace. There's no one that knows gamma radiation like you do. If there was, that's where I'd be.
The Avengers

Which ties in nicely to what Erik says:

Erik Selvig: I knew this scientist... a pioneer in gamma radiation. S.H.I.E.L.D showed up and... umm. He wasn't heard from again.
Thor

Note though that it isn’t directly S.H.I.E.L.D. in The Incredible Hulk for most of the time even if Ross mentions working with them. However, in some of the tie in comics, such as The Incredible Hulk: The Fury Files, we see that S.H.I.E.L.D. have been watching Bruce even if they decide not to use him at that point in time.
S.H.I.E.L.D. show up a few more times watching Banner and keeping a track of him. However, they are never directly involved in what made Banner disappear: that was Ross and his teams doing. As such it seems like Erik’s quote is either generalising/conflating the groups or there is yet more we don’t know about.
Of course something is alluded to in The Avengers when Nat goes to recruit Bruce by stating that they never lost him.

Banner: Are you here to kill me, Miss Romanoff? Because that's not gonna work out for everyone.
Natasha: No. No. Of course not. I'm here on behalf of SHIELD.
Banner: SHIELD. How did they find me?
Natasha: We never lost you, doctor. We've kept our distance, even helped keep some other interested parties off your scent.
The Avengers

