Everyone loves Keras and here’s a great article on why that is.
Today, the Deep Learning ecosystem is much more mature, so thankfully one can get by with learning fewer frameworks. While many excellent frameworks have been released over these intervening years, and are being used in specialized niches, the major ones are Keras, Tensorflow, and Pytorch. Pytorch became popular because of its eager execution model, which Tensorflow did not allow, and which Keras hid behind its cleverly-designed API. Keras has since been subsumed into Tensorflow as tf.keras, but the original Keras lives on as well, with an additional CNTK (from Microsoft) backend. For its part, Tensorflow, in its 2.x incarnation, has embraced Pytorch’s eager execution model, and made tf.keras its default API.