There are multiple CT repo, run by various vendors. A very good aggregator that allows searching is https://crt.sh/ https://crt.sh/, which is run by Comodo and

There are multiple CT repo, run by various vendors. A very good aggregator that allows searching is https://crt.sh/ https://crt.sh/, which is run by Comodo and tracks multiple CT services. Enter in a domain name, and you can see all certs known for that domain.