http://caseinterviewprep.deloitte.com/
Practice a case interview | Deloitte

Assessment Centre
https://www.jobtestprep.co.uk/assessment-centre-case-study

McKinsey
Interviewing

Bain
https://www.bain.com/careers/interview-prep/

Morgan Stanley
https://www.morganstanley.com/people-opportunities/students-graduates/resources/interview-preparation