HayScout is a private search engine that was launched last week. It is a paid service, and it offers a web search that is free from ads, data collection and trackers. The search results are a customized version of the Bing search results. The free version allows for 50 queries a month. If you pay $5 per month you get up to 2000 queries per month, and you gain the ability to block up to 50 domains in the results. This allows you to filter out unwanted or low quality websites.
The HayScout results are comparable the Bing-based search engines like DuckDuckGo. The main difference is that Hayscout is ad-free, whereas DuckDuckGo includes Amazon advertising.
Unfortunately, payment for Hayscout is only via credit card and requires an email address and zipcode.
In regards to search engine APIs, it seems that Oath (Yahoo) are pivoting their search API into some kind of advertising platform. Google shuttered their API in 2010. Therefore only viable remaining commercial options for sourcing search results are Bing and to a lesser extent Yandex. If Bing were to shutter its API it would become nearly impossible for another player without substantial capital at their disposal to enter the search market.