SearXNG is a free internet metasearch engine which aggregates results from various search services and databases. Users are neither tracked nor profiled. It's a fork of the original Searx but has diverged in some important ways. Theming aside, it's more mobile friendly, the translations are up to date, preferences (such as "which engines are reliable on this instance") have been updated, and metrics for detecting broken or failing search engines supported by the software have been added (opt-out). No additional filters or proxies are needed.
A meta-search engine a little like Searx. Not as featureful, not many features, but for something quick and dirty to just get stuff done it seems to do the job. No Javascript. Self hosted. Strips tracking codes out of URLs it finds. Lightweight - no Composer stuff, all self contained. Has an API but not REST.
A meta-search engine for ecommerce sites. Search for something to buy and get links to multiple sites where you can get it. Search a particular country, or search globally.
A search engine for public records archives and sub-searches around the country.