In the timeline and calendar view, you should be able to set the colour based on the colour for the task type option that it is set to. For example, if I have a custom task type with the option “on hold” that is the colour red, I would like that task to appear red in the timeline view.
Hi @RowanBCF, welcome to the forum 
Great idea, I’ve also voted!
If they ever add custom type color support to timelines and reports, I’ll finally be able to stop using the redundant custom field I have to keep active, added everywhere, and synced with rules just to handle this use case. 