Seems like a good time to link to this curated list of pipeline toolkits (not all python).

https://github.com/pditommaso/awesome-pipeline/blob/master/R...

https://github.com/common-workflow-language/common-workflow-...

Also, whenever these conversation of flow-based / piplining tools come up, I always like to point people to Common Workflow Language to remind people that there is an attempt at standardizing workflow descriptions so that they can be used with different packages:

https://www.commonwl.org/