Here are a few more Singularity containers, that we at Sylabs have put together:

Caffe
Caffe is a Deep Learning framework.

https://github.com/sylabs/examples/tree/master/machinelearning/caffe
Singularity Definition File

Horovod
Horovod is a distributed-training framework for TensorFlow, Keras, and PyTorch. The goal of Horovod is to make distributed Deep Learning fast and easy to use.

https://github.com/sylabs/examples/tree/master/machinelearning/horovod
Singularity Definition File

MongoDB
MongoDB is an open-source DataBase Management System (DBMS) that uses a document-oriented database model which supports various forms of data.

https://github.com/sylabs/examples/tree/master/database/mongodb
Singularity Definition File

Nginx + PHP
Nginx is open-source software for web serving, reverse proxying, caching, load balancing, media streaming, and more.

https://github.com/sylabs/examples/tree/master/http-server/nginx-php-web-server
Singularity Definition File

Orange
Orange is a data-mining environment used for Machine Learning and data visualization.

https://github.com/sylabs/examples/tree/master/machinelearning/orange
Singularity Definition File

We have also posted the relevant files for Spark and RStudio.