1. 0B6 is for CaseTeamMember object.

https://www.infallibletechie.com/2019/04/0b6-sobject-prefix-salesforce.html

2. 301 sObject Prefix in Salesforce is for Flow entity.

https://www.infallibletechie.com/2022/10/301-sobject-prefix-in-salesforce.html