Here is a single LWC Open Source App for you : https://salesforcelwc.herokuapp.com 

Sample use case :

1. How do I check my platform event JSON message structure ?
2. For insert which are all fields included in my CDC JSON body ?
3. For Update which are all fields included in my CDC JSON body ?
4. For Delete do I receive only the sObject id or anything else ?
5. Push Topic is firing only for Insert/Update or for Delete also ?
6. How do I get Account and its Contact in a single tabular structure(SOQL) ?
7. How do I test my Apex REST API class created today without an external endpoint, etc.

Post your experience/feedback  with me. I will try to do any improvement if required.