Let me see if I can put this to bed, though it is not a terribly satisfactory answer.

A Lightroom preset is a collection of settings, so once applied, the preset itself is not needed (by lightroom) to render the image. That is in contrast to something like a camera profile - the profile is used each time the image is rendered, so if you have a custom profile and lose it, the profile's impact is lost, and Lightroom reverts to a default value.

Further, a preset adds or replaces other settings. So if you process an image with preset1, then preset2, then manual settings, the result is a mixed together group of settings. Settings in preset2 of the same slider will overlay preset 1; of mutually exclusive sliders will then have both present.

You can take an image at any time, and save its current settings as a new preset, so you can recreate a preset in that fashion EXCEPT it will include any changes you may have made afterwards, for example if you applied Preset1 then changed the shadow slider, and save it - you get a different shadow slider. (You can limit which settings are saved, of course). You can use the develop history to step back to a point with just the preset, if it was the first thing applied.

Further complicating this, once you apply a preset then make any other change, the metadata for the preset (i.e. what you get if you filter by preset) just becomes "custom". The only place I think the act of applying the preset is retained is in the develop history, which is accessible to plugins and in the history view, but is not something you can (at least in vanilla lightroom) sort or select by.

So if your goal is to recreate all your presets, I would start first by seeing if they show up in the metadata filter for presets at all. If so, you can find an image that had it applied and no prior or subsequent changes; save it's develop settings, done.

For others, you have to hunt in history to find a point at which the develop preset was applied, and revert to that point, and save the then-current develop settings. How to know which settings were saved in each preset (i.e. which saved and which excluded) - no idea, unless you just know.

Update 6/7/2017: The following answer may also be of help if you want to access the catalog directly: here