The Sustainable Use License

Created by n8n, the Sustainable Use License seems like a good option for new SaaS platforms:

Our goals when we created the Sustainable Use License were:

1. To be as permissive as possible.
2. Safeguarding our ability to build a business.
3. Being as clear as possible what use was permitted or not.

The license comes with three limitations:

1. You may use or modify the software only for your own internal business purposes or for non-commercial or personal use.
2. You may distribute the software or provide it to others only if you do so free of charge for non-commercial purposes.
3. You may not alter, remove, or obscure any licensing, copyright, or other notices of the licensor in the software. Any use of the licensor's trademarks is subject to applicable law.

The main points here are: use and modification only for internal business purposes (that’s the AWS clause, to prevent getting the Elastic treatment) and only being able to distribute/provide to others for non-commercial purposes.