python

https://www.quora.com/What-about-the-future-of-Python-and-Django
Twisted Engine help you build Server, Web Server, Mail Client, simple publish/subscribe server and many more asynchronous things.

Tornado is a scalable, non-blocking web server and web application framework.

Flask is microframework for building Microservices.

Sanic, Python 3 web Framework is relatively new but strong async Framework which handle millions of user with blazing fast speed.

Django is Full Flegde Battle Ninja(Python Web Framework), whatever you want in framework, you will find within it. It even support synchronous and async both now.

Data Science:

Core: Numpy, Pandas, Scipy

Visualization:Matplotlib, Seaborn, Bokeh

Machine Learning: Scikit Learn

Deep Learning: Theano, Tensorflow, Keras

Natural Language Processing: NLTK, SpaCy,Gensim

Data Mining, Statistics: Scrapy, Statsmodels