You can try the websites below to find a job.
They're not only for the Tokyo area, but I think you can set parameters to your search.
Gaijinpot Jobs: https://jobs.gaijinpot.com/
Many job offers tailor-made for foreiginers living in Japan.
Wantedly: https://www.wantedly.com
This one is in Japanese, but Japanese companies use it to find employees, so if you japanese is basic, you can google translate the website.
Active Connector: http://www.active-connector.com/home/
This company traces your profile and tries to match you with one company. Absolutely recommended.
Craigslist: https://tokyo.craigslist.jp/search/jjj?lang=en&cc=us
Craigslist can be more than classified ads. You can find lots of job opportunities there.
Jrec-in portal: https://jrecin.jst.go.jp/seek/SeekJorSearch?fn=4&ln=1&prefecture_9=00040
If you already have doctorship, this website is recommended
And last but not least, other websites to find work in Japan:
Jobs in Japan: https://jobsinjapan.com/
Daijob: https://www.daijob.com/en/index.html
CareerCross: https://www.careercross.com/en/
I wish you the best of luck in finding work in Japan!