Chromium > Settings > Search engine > Manage search engines > Add

Google
SE: Start
Keyword: !g
URL with %s in place of query: https://www.startpage.com/sp/search?query=%s&cat=web&pl=opensearch&language=english
Suggestions URL with %s in place of query: https://www.startpage.com/cgi-bin/csuggest?query=%s&limit=10&lang=english&format=json

DDG
SE: Duck
Keyword: !d
URL with %s in place of query: https://duckduckgo.com/?q=%s
Suggestions URL with %s in place of query: https://duckduckgo.com/ac/?q=%s&type=list

DDG Lite
Keyword: !dd
URL with %s in place of query: https://html.duckduckgo.com/html/?q=%s

Youtube
SE: Yewtube
Keyword: !y
URL with %s in place of query: https://yewtu.be/search?q=%s

Youtube (Google)
SE: Youtube
Keyword: !yt
URL with %s in place of query: https://www.youtube.com/search?q=%s

Wiki
SE: Wiki
Keyword: !w
URL with %s in place of query: https://en.m.wikipedia.org/wiki/%s

Wiki ru
SE: Wiki ru
Keyword: !wr
URL with %s in place of query: https://ru.m.wikipedia.org/wiki/%s

No Search
Keyword: !n
URL with %s in place of query: http://%s