nn-search is described as 'simple application for searching words using their part-of-speech tags. For example, it can find a chain of tags like "DT NN VB" that may correspond to such sentences in a text as "a tree grows" or "the dog barks"'. There are three alternatives to nn-search for Windows, Linux and Mac. The best alternative is XSearch, which is free. Other great apps like nn-search are SCAN (Smart Content Aggregation and Navigation) (Free) and nn_search2 (Free, Open Source).
SCAN (Smart Content Aggregation and Navigation) is a personal semantic content manager for desktop users. It combines search, text analysis, tagging and metadata functions to provide new user experience of desktop navigation and personal document management.
nn-search2 is a part-of-speech tagging and text search utility based on NLTK, TextBlob and matplotlib. It uses state-of-the-art pos-tagger based on Averaged Perceptron which provides fast and accurate results.