The Czech is called RSJ, the israeli is called Final. I can’t find the british ones now. Here’s a list for you if you want more names: https://www.planetcompliance.com/2017/03/26/introduction-hft...

There are tons. I don't know which ones he's thinking of, but off the top of my head: PDT, Jump Trading, Domeyard, Two Sigma, DE Shaw, Jane Street, Citadel.