It has been a while since I have seen a step 2 decision, but I saw one last week. A step 2 decision means a disability claim is denied at step 2 of Social Security's sequential evaluation. That step is a determination of whether or not your impairment, or combination of impairments, is "severe" under Social Security's rules.
It is pretty rare to see a step 2 decision, because the bar is set pretty low. Social Security Ruling 85-28, entitled Titles II and XVI: Medical Impairments That are Not Severe, states in part:
A claim may be denied at step two only if the evidence shows that the individual's impairments, when considered in combination, are not medically severe, i.e., do not have more than a minimal effect on the person's physical or mental ability(ies) to perform basic work activities. If such a finding is not clearly established by medical evidence, however, adjudication must continue through the sequential evaluation process.
As a practical matter, you see a step 2 decision when the judge wants to deny the claim and knows better than to throw the claimant into the briar patch of steps 4 and 5. For example, in this recent case, past work was "very heavy," and the claimant is over 60, and would grid "disabled" at step 5 at anything less than medium exertional work. Under these circumstances, from the perspective of a denying judge, it is worth a try to write a step 2 decision.