Name:
Miniconda (The package is called miniconda but the library in bash is called conda)

Homepage:
https://conda.io/miniconda.html

Why should this be included:
It's an alternative of pip that's strongly preferred by data scientists and some python developers due to dramatically improved ease of use

Open source:
Yes

How many users:
Most to all of the the data scientists I've worked with and some of the Python developers. I don't know how many of those use Solus right now, but they're a big part of Linux users

Link:
https://github.com/conda/conda
https://docs.anaconda.com/anaconda/packages/pkg-docs

Additional Notes:
Having both the current python3 version (at this time python3 3.6) and the Python 2.7 version is important due to the version split in python.