I'm updating my resume and I want to know if I should put the name of the clients I worked for as a contractor or only the consulting company?
I have worked with 3 clients inside this company and the projects were very different between each one.
See my related answer here: Can I claim Ex-FAANG if I was a contractor at Amazon?
Assuming there's no confidentiality issue, you can name the client if you feel like you got a true feel for the company culture and coworkers. Your next job may ask for references at the company, so you should be prepared for that.
If the client names are prestigious, you should definitely include them. As long as it doesn't look like you actually worked for them (this would be lying, which is terrible), you should be okay.