The electric breakdown in air produces all sorts of radical, ions and some more stable compounds. The temperature created in the current flow during discharge can be quite high, high enough to scramble most gas molecules into all sorts of small pieces which recombine (or fall apart) into other species. I mean you can smell ozone around high voltage equipment - apparently you didn't know that. As for what specifically is formed, wow, that's a really hard question to answer. The more serious question is what is detected? (Because a chemical has to persist for "a while" to be detected, instead of only existing for an instant to have been "created"). What persists long enough to be detected depends on what is around. Especially important are pollutants like sulfur dioxide and organics. In pure humid air, you've got the obvious ions, and species like H2O2, NOx, O3. I wouldn't expect any NH3 (ammonia) but I wouldn't be too surprised if it was found, either. This may not seem related, but it is: did you know that you can detect x-ray emissions from Scotch Tape being pulled off of a surface when it's in a vacuum? (They don't detect it in air, not because it doesn't happen, but because the air absorbs the (faint) x-rays before they can be detected). There's a LOT of chemistry that is going on all around us that is just happening too quickly for us to see. And of course if you're into scifi, you know about the experiments with lightning (arc discharge) making polymers which used to be the most popular explanation of how life originated on Earth. 104
Electric discharge is actually NOT well understood. What we do know is that it is definitely powerful enough to make all sorts of (random) chemicals. They use electrical discharge to cut holes (with very precise dimensions) in thick, thick steel. It packs a wallop. So, to answer your question in a general way. Take H, C, O, N as the (atomic) constituents of air (as CO2, H2O, O2, and N2) and assemble ANY molecule with say, 3 or fewer of any of them. Chances are some of that is made. CO (carbon monoxide)? sure. NO, NO2 ? I'd bet on it. H2O2? Probably...So write this HwCxOyNz and vary w, x, y and z from 0 to 3 and you probably have listed something which has at least transient existence. H, H2, H3 (er...maybe) N, N2 (already present), N3 etc., HN, H2N, HN2, etc. etc. 662