I am not native English speaker and often times I use Ozdic to find the correct word choice. It's good overall but its database is quite limited. I think a tool based on Word2Vec should be able to do a great job for finding collocations/cooccurance.
With skip-grams, given a window size of n words around a word w, word2vec predicts contextual words c; i.e. in the notation of probability p(c|w). Conversely, CBOW predicts the current word, given the context in the window, p(w|c).
I am looking for a tool that takes a sentence with a blank spot as input and gives alternative options for the blank spot as an output.