Identifying languages with some specified language feature is a frequent activity, both for natural languages and conlangs. WALS and CALS are popular resources for seeing how common various options are. But they don't have every feature, nor every language.
The Linguistics site has a tag, list-of-languages. Tagged questions can ask about languages which meet a particular set of criteria, and are usually allowed to stay open, despite the usual Stack Exchange rule against list questions. (Only 6 out of 127 have been closed so far.) This seems to work quite well. They're not necessarily the best questions ever, but they meet a need that otherwise wouldn't be met, and they have so far avoided the problems which plagued other sites' list questions.
Do we want to allow similar questions here? And do we want all kinds of these list-of-languages questions, or only the ones asking about linguistic features (those are the only ones common or allowed on Linguistics.SE)?
Here are some we've received already:
Questions about linguistic features
Questions about social features or purposes
Questions about conlang origins