The three I've used in my career on wall street have been the following:
Jenkins: Far and away the most popular. I've used this at all the roles/banks I've worked at. I've made projects work with C/C++, Python, Java, Scala, Rust, and Haskell.
Gitlab CI/CD: Used it at BNP Paribas and it has built-in CI/CD capabilities directly integrated with its version control features. It supports C/C++ projects and allows you to define CI/CD pipelines using .gitlab-ci.yml configuration files.
Github Actions: A more recent development for me at my current role at Morgan Stanley. GitHub Actions allows you to automate workflows directly within your GitHub repository. It supports C/C++ projects and provides flexibility in defining custom workflows using YAML syntax. Really the only pain points are us having to work with the internal 'morganization' of things for security purposes. Otherwise it flows pretty nicely.