If Darwin is to believe, interjections are emission of sounds efficient in highest degree as means of expression, rather, vocal expression. Interjections show rather than say. So gestures and postures enjoy all the more important roles in them. Contexts and overlapping are thus an intrinsic part of it. What you are looking for is cultural, standardized vocalisations. On this score, we have to rely on the native speaker's judgement or intuitions. Culture, speech, modulation and sense of propriety and intonation differ from language to language. However, here is an indicative though not exhaustive list of condescending interjections, but guaranteeing no exclusive right to agreement alone.
- Olè! (from Spanish)