Initially, I learned C#, or rather, I grasped the basics and managed to write a calculator for my own usage.
-I also worked on developing a game launcher that interacts with a database.

However, I've run out of ideas and motivation for C#. My intention was to gain understanding and then transition to another language that would provide more opportunities to earn money. Unfortunately, freelance platforms rarely demand C# programmers, mainly due to its lack of cross-platform capabilities. Personally, I desire to work on diverse systems and have even started exploring Linux.

I've considered game development and found unity3d appealing, especially for its utilization of C# scripts. At present, I'm attempting to create an android game. Nevertheless, I still aspire to take on freelance projects.

Considering my goals, I need recommendations on which programming language to switch to in order to work freelance, be cross-platform, and capable of Object-Oriented Programming (OOP).

To my disappointment, Java doesn't seem to be a suitable choice. It feels too similar to C# and I struggle to find helpful resources.

If you're looking for a programming language that can provide more freelance opportunities, is cross-platform, and supports Object-Oriented Programming (OOP), there are a few options you can consider:

1. Python: Python is a versatile language with a large and active community. It allows you to develop for various platforms and has a wide range of libraries and frameworks for web development, data science, machine learning, and more.

2. JavaScript: JavaScript is the language of the web and is highly demanded for web development. It can also be used with frameworks like React Native or Electron to build cross-platform mobile or desktop applications.

3. Go: Go (or Golang) is a language developed by Google that focuses on simplicity, efficiency, and concurrency. It has gained popularity in recent years, particularly for building high-performance web services and scalable systems.

4. Rust: Rust is a system-level programming language that offers memory safety, concurrency, and performance. It's gaining traction in areas such as systems programming, game development, and networking.

5. Kotlin: Kotlin is a modern language that runs on the Java Virtual Machine (JVM) and is fully interoperable with Java. It has become the preferred language for Android development and is also used for server-side development.

Here are a few more programming languages worth considering for freelance work, cross-platform development, and OOP:

1. TypeScript: TypeScript is a typed superset of JavaScript that compiles to plain JavaScript. It adds static typing, which enhances code maintainability and enables better tooling support. TypeScript is widely used for frontend and backend development and is especially popular in the Angular framework ecosystem.

2. Swift: Swift is a modern, powerful, and intuitive programming language primarily used for developing applications for Apple's iOS, macOS, watchOS, and tvOS platforms. With its clean syntax and robust features, Swift has become a go-to choice for iOS developers.

3. C++: If you're interested in low-level systems programming, game development, or performance-critical applications, then C++ might be a good fit. It offers a high level of control over memory management and is widely used in various domains like gaming, embedded systems, and high-performance computing.

4. Rust: Rust, as mentioned earlier, is a systems programming language that focuses on safety, concurrency, and performance. If you're looking to work on projects that require security, speed, or low-level control, Rust can be a great choice.

5. PHP: PHP is a popular server-side scripting language used for web development. It powers a significant portion of the internet, especially for building dynamic websites and content management systems. PHP has a vast ecosystem of frameworks and libraries, making it suitable for freelance web development projects.

few more programming languages you can consider:

1. Ruby: Ruby is a dynamic, interpreted language known for its simplicity and productivity. It has a strong focus on developer happiness and is widely used in web development, particularly with the Ruby on Rails framework. Ruby's elegant syntax and focus on readability make it a popular choice for freelancers.

2. C#: Although you mentioned running out of ideas and motivation for C#, it can still be a viable option for freelance work, particularly in the domain of Windows desktop application development or game development using Unity3D. C# has a robust ecosystem and is highly compatible with Microsoft technologies.

3. Scala: Scala is a language that combines object-oriented and functional programming paradigms. It runs on the Java Virtual Machine (JVM) and has gained popularity for its scalability and support for concurrent programming. Scala is often used in big data processing and web application development.

4. Haxe: Haxe is a modern, open-source language that allows cross-platform development. It can compile to various targets, such as JavaScript, Flash, C++, and more. Haxe has a strong community and offers excellent versatility for building games, web applications, or mobile apps.

5. Dart: Dart is a language developed by Google, primarily used for building web and mobile applications. It can compile to efficient JavaScript code, making it suitable for web development, and it's also the language used by the Flutter framework for creating native mobile apps for iOS and Android.

Seek out opportunities for fulltime or halftime positions within companies that have a development department. Offer yourself as a super intern, willing to work for free or at a reduced rate. As long as you have the desire, there is a chance for success.

However, it's important to note that freelancing is no longer the utopia it once was. The freelance market has become highly competitive and professional. Without sufficient experience, the likelihood of failure is high. Therefore, it is crucial to focus on your own personal development.

Begin by starting in a smaller company and strive to become a medium or senior-level employee. From there, gradually move on to larger firms. By continuously gaining experience, you will eventually achieve success. Remember, it's important to take risks and take action in order to progress.

Depending on how quickly you want to begin earning, there are two possible answers to your question. If immediate earnings are your priority, then PHP is the way to go. This language is currently in high demand, and learning it is relatively easy.

However, if your focus is on earning in the long term, particularly within the next decade, then JavaScript is the better choice. This language is expected to be widely used in the near future, not only for web development but also for desktop applications across all platforms. Additionally, frontend development is currently a trending field and is projected to remain in demand for several years to come, ensuring long-term job security. So, by choosing JavaScript, you can ensure that you will not be out of work and will have ample opportunities for growth and success.

It's worth noting that both PHP and JavaScript are valuable skills to have in today's tech industry. By mastering either or both of these languages, you can open up a multitude of career prospects and stay competitive in the job market.