Is there a way to set up alert/notification for when the list view reaches a certain number (ie getting close to full)?
Not directly. The list view threshold isn't actually a limit, but a configured threshold setting (though not currently configurable in office 365). If you wanted to manage this, you should setup some kind of regular process to report and monitor this. There are some third party tools that can help or you can build something custom. You could potentially do a workflow that collects the info for all of the lists and libraries on a given site, but you want to be very careful since on extremely large sites or sites with very large lists and libraries those operations could really slow things down.
You could set up a simple scheduled workflow that counts the items in the list (for example each week) and sends a mail notification once it contains a specific amount of items.
Is the threshold affecting your work? Technically lists can contain millions of items so you shouldn't bother about the threshold. It only comes into play if a view returns more items than the threshold allows and if you use view filters based on columns that weren't indexed before. With indexing and good view management the threshold shouldn't affect your work.
Here you find some more information about this: Manage large lists and libraries in SharePoint - SharePoint
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