I think these kind of sentences are the true "kindergarten teacher" sentences in disguise. The idea of looking for something old or multiple old things is common but a complete-sounding sentence with "régieket" sounds just as bizarre as "looking for old ones" in English.
What do you guys think? I find a sentence like this much more tiring than a sentence that has a usual structure with odd meaning. In the latter case, the idea to express is rare but the way to express it is common. Here, a common idea is expressed in an odd way... the sentence looks like an innocent neutral complete sentence while it structurally can't sound like one.
That's "Régieket keresek" though. It doesn't look like a complete sentence. "Péter régieket keres" looks like a neutral report about what a third person is doing/does regularly - and it fails to be natural with this. "Régieket keres" itself would sound more legit in my opinion - although we may argue whether it would be a good idea to start adding intentionally "contextual" sentences.