Are there any alternatives for Visual Studio on Ubuntu?
I searched on Google and I could not find anything.
Your question leaves a bit to be desired, but from what I interpret you are asking for IDEs with C# support that can run on Ubuntu.
I would highly recommend Visual Studio Code (link)
Alternatively you have JetBrains Rider, which is a fabulous, but paid IDE.
If your question is if you can run Visual Studio on Ubuntu, the answer is no.
If you are looking for IDE then MonoDevelop or Visual Studio Code are good alternatives.