Datasets that haven't been put into a repository or archive can be more difficult to find, however it's worth searching more broadly if you haven't found suitable data using the previous strategies. People sometimes make datasets available through personal websites, or through sites related to research groups or projects. The best way to find these datasets is by using a search engine to search across the internet.
Use your favourite search engine and some or all of the keywords that you identified when you considered what data would be useful to you to help get relevant results. Use operators, such as AND and OR, or advanced search interfaces to refine and filter your search. If you want advice on constructing searches, contact your Academic Liaison Librarian.
Example search netCDF climate data => returns results that include: UCAR Climate Data Sets Globally Downscaled Climate Data NOAA/NSIDC Climate Data Record among others.
Once you find a dataset that you're interested in, make sure to assess it for relevance and quality before you start using it.
As you are searching across the internet, rather than just places that store datasets, your search is likely to include a large number of results that aren't pertinent to you, including results for many things that aren't datasets at all. This means that you will need to spend more time looking through the results and running through various combinations of search terms to find the results that you need.
Data repositories and archives often have certain quality requirements that need to be met before a datasets is allowed to be submitted there. However, as anyone can create a website and add a dataset there, you may encounter more poor quality datasets when using a general internet search. It's extremely important to consider the trustworthiness of the source and the quality of the data that you find in these cases. For example, data found on an official government website might be more trustworthy than data found on a personal website.