Open source contribution refers to the act of participating in the development and improvement of open source projects. Open source projects are software, resources, or tools whose source code is publicly accessible, allowing anyone to view, use, modify, and distribute the code. Contributing to open source projects is a valuable way to learn, grow, and give back to the community while gaining experience and building a strong portfolio.
contributing to open source projects can be a rewarding and fulfilling experience as it not only helps improve the projects but also helps you develop your skills, expand your network, enhance your portfolio and get a Job.

Here are 16 paid open source programs you can apply to :
1) Google Summer of codes
Google Summer of Code
Google Summer of Code is a global program focused on bringing more developers into open source software development.
summerofcode.withgoogle.com
Paid — $1500 for short-term projects, $3000 for long-term projects and a maximum of $3300 for short-term projects and $6600 for long-term Projects
12 weeks
Application Period — March to April
Project Period — May to August
Google Summer of Code is a global, online program focused on bringing new contributors into open source software development. GSoC Contributors work with an open source organisation on a 12+ week programming project under the guidance of mentors.