SklearnEstimator: a base class for scikit-learn estimators to be used with AllenNLP. There are a few subclasses for now: DummyClassifierEstimator, SvcEstimator, PipelineEstimator, and StandardScalerTransformerEstimator; corresponding to DummyClassifier, SVC, Pipeline, and StandardScaler from scikit-learn. Feel free to add more as it's likely just little code.
SklearnTrainer: train a model that uses a SklearnEstimator.
Optional:
SklearnModel: a simple class that contains a SklearnEstimator. You can choose to implement your own if it doesn't satisfy your needs.
SklearnBatchSampler: a convenient batch sampler that grabs all items from the dataset together, so there's only one big batch.