The lowest I’ve seen in Google Search Console really depends on the site and the metric you're referring to (like average position, CTR, or indexed pages), but for something like average position, I’ve seen it get as low as 1.0 for branded or highly targeted keywords.
As for a site-wide average, it varies a lot depending on the niche and the size of the site. Generally, people aim for an average position under 20, ideally under 10, to start seeing meaningful organic traffic. For CTR, a 2-5% average site-wide is fairly common, though some pages can obviously perform much better.
In terms of indexed pages or overall site performance, having a high percentage of your pages indexed and actually receiving impressions is a good sign. If only a small fraction of your content is getting visibility, it might be worth auditing for quality or relevance.