The best alternatives to SlackBucket are Sherlybox, Cosmic, and Baccus. If these 3 options don't work for you, we've listed a few more alternatives below.
What do you think of SlackBucket?
AssemblyAI— Speech-to-Text API with superhuman accuracy
Cosmic is an API-first headless CMS. Developers get tools to deliver content to any website or app and content creators get an intuitive content management dashboard.
Horcrux Email Backup is an easy to use Email Backup product for the Mac. Our internet worlds revolve around emails, the protection of them hasn’t been on many of our minds until calamity strikes. In case that happens, it'll let you move your emails with a click.