There are several websites and online platforms that can be valuable resources for problem-solving across various domains. The “best” problem-solving websites can depend on your specific needs and interests. Here’s a list of some popular websites that can help with problem-solving:

1. Stack Overflow (stackoverflow.com): A community-driven Q&A platform focused on programming and software development. It’s a go-to resource for coding and technical problem-solving.
2. Quora (quora.com): A platform for asking and answering questions on a wide range of topics. You can find solutions to various problems and get insights from experts in different fields.
3. Math Stack Exchange (math.stackexchange.com): A community for mathematicians and math enthusiasts to ask and answer mathematical questions.
4. Physics Forums (physicsforums.com): A resource for physics-related questions and discussions, covering a wide range of topics in physics.
5. Ask MetaFilter (ask.metafilter.com): A community-driven question-and-answer platform covering a broad range of topics, from technology to life advice.
6. Answerki (answerki.com):  A platform for asking and answering questions on a wide range of topics. You can find solutions to various problems and get insights from experts in different fields.