This is a rather brutal looking batch of Assemblers. Everyone is a bit off model, with a somewhat more savage and ferocious look. It's the work of Franc Reyes and if my memory serves, it's the back cover of FantaCo's Avengers Chronicles.
This is a group of supertypes that lives up the name "Avengers".
UPDATE: My memory did not serve very well at all. I've been very rightly corrected that the source for this was The Marvel Comics Index #3. Here's the front cover, a sturdy piece of art by Neal Adams.
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