My guess would be:
In Britain / Europe: Wiener Radio Werke (WIRAG), Mullard, Hendon Works, Valvo, Hyperlec Brive, La Radiotechnique, Standard Telephones and Cables Ltd (Thorn), Thorn-AEI Radio Valve, Matsushita Electronics, Philips Electronics, Marconi, English Electric Valve Co., Toshiba,
In the US, Amperex, Bendix, DuMont, Elmac (Eitel-McCollough), RCA, Westinghouse, Sylvania, Zenith, Raytheon, GE, Western Electric, Philips, Superior, United Electronics, Machlett, Taylor (Cetron-Taylor), Lewis & Kaufman, Penta Labs, Tung-Sol, Hytron (CBS-Hytron), Vacuum Tube Products, Varian Associates, Litton Industries, Electrons Inc.
Just a guess.
https://www.vivatubes.com/identifying-vintage-nos-vacuum-tubes-by-brand-country-and-eia-code/