I don't know of any tools. When I perform a code review, I look for the following things (this is not an exhaustive list but will get you started);

1. Adherence to the standards and practices you have established.
2. For each automation that has an exit point, do the links all reach one?
3. Are there any duplicate yellow lines coming out of any execution path?
4. Are you breaking loops before reaching an exit point?
5. Are the automations not too long?
6. Are any uses of credentials marked as sensitive?
7. Are there any variables or other items marked as global in-scope unnecessarily?
8. Are the automations readable?
9. If it is possible to perform interrogation; are there any ambiguously matched controls?
10. Are there any duplicate automations?
11. Are there any elements used for testing that are left in the solution projects?

Thank you very much and I will start preparing a checklist based on the list.