As the title suggests, I think it would be a really cool idea if Domo had a recycle bin.  This would be a paid premium feature, and I think it would be a boon from a maintenance/emergency perspective.  While sandbox is great and helpful for recovery in situations where things have been accidentally deleted, it can still be time consuming to re-deploy, fetch and restore historical data, re-establish user/groups access etc.  Re-deployment also causes a change of object IDs and can affect other objects/processes.  Particularly SQL based views that reference datasets by ID, any hardcoded object ID references in jupyter notebooks, external automation scripts etc.   
A recycle bin would allow owners of objects or admins to quickly restore a deleted item quickly.  Here's how I imagine this working after the feature has been paid for.
Admin > Site settings
A checkbox to enable the recycle bin feature along with a dropdown allowing you to select how many days of retention before items are actually permanently deleted.  The amount of days you select determines your overall cost per month (with a max of say 30 days).
Grants
New grants can be added to roles that let you use the recycle bin or manage the recycle bin (thus allow you to restore objects from any user).  Admins would automatically have this grant.
Domo UI
Once enabled, a recycle bin shows up in the Domo interface.  When an item is deleted, roles with the proper grants will see a categorized list of the deleted objects they own (or all items if they have the managed grant).  It would also display whether or not the item is in an existing repository.  If it is part of a repository, perhaps it can also show information about the repository and its current version #, etc.  If the object is not part of a repository, that information would be blank with a button that would optionally allow you to add it to a new or existing repository.  It would also show the objects internal ID and maybe an indicator to show that the deleted item broke the lineage of other objects along with a tooltip that lists all of objects affected.  
Users can right click on any item in the recycle bin to restore it immediately.  The restoration would restore everything about that object as if it was never deleted in the first place. Maintaining the existing object ID, data and metadata, user group access, PDP etc.  Basically, a full 1-to-1 restoration.  Once restored, it no longer shows in the recycle bin.
Object Types
In its current state, sandbox supports a limited number of object types.  The recycle bin however would support anything subject to deletion.
Cards
App Studio Apps
Dashboards
Connectors
Domo Datasets
Dataflows
Jupyter Notebooks / Workspaces
File Shares (along with any content)
Pro-code Apps / AppDB Assets
User / Groups
Workflows / Code Engine
Alerts
Views
Sandbox Repositories
AI Projects
Accounts
(And other objects I haven't thought of)
I realize there is a lot more to consider here as it does overlap with sandbox a bit.  I also realize that restoring certain deleted objects would require any other deleted dependencies to be automatically restored as well.  It's a crazy, complex idea with a lot to consider.  But, if this can be made to somehow work in tandem with sandbox, I think it would be extremely useful.  I imagine it would also make Domo Support's life much easier when emergencies occur. 😉