It is not possible to create Flow and make it available for whole tenant to be used in any library/list in SharePoint site.
As there is possible to pick Flow from public gallery. It will be nice to have something similar on tenant level as mentioned in previous post here Reusing flows post.
It will be nice to create something that will be called Organization gallery so the Flow will be findable here for any user shared with.
It's now possible to reuse copies of flows inside of your organization: https://flow.microsoft.com/blog/send-a-flow-as-a-copy/
There should be the ability for organizations to have a curated set of Flow templates so they can be easily reused. An organization administrator should be able to approve submitted templates to make sure they are suitable.
This would be great.
It would also be great if you could push a flow out to your whole organisation.
So now that we can export flows, is it possible to import flows to be used with a new list?
We are working on a feature so a user can share a flow template to other users within the organization.