Dread gave the broad-brush answer. Ask about specific scales & subjects. The following list is not complete. Feel free to chime in with more
1:96 -- Old Steam Navy - ACW, Cottage Industry - ACW
1:192 -- Flagship Models (ex Lone Star) - ACW
1:200 -- Verlinden - ACW
1:350 -- Yankee Modelworks (ex Blue Water Navy) US, IJN, Russian ships & subs, WWII to modern; Iron Shipwright - US, RN Spanish-American War to present, Classic (ex Gulfsteam, ex Accurate Miniatures) - USN WWII; White Ensign Models - RN, USN WWII to modern; Resin Shipyard - Canadian, YS Masterpiece - USN Spanish American War
1:400 -- L'Arsenal - French
1:700 -- KoboHiryu - USN & IJN WWII, Waveline - various have become PitRoad Plastic kits; HP Models - All countries, all periods, DocModell - various; B Resina - various; JAG Collective USN Postwar Gators & Auxilliaries, WEM - RN; Classic Warships -- Pearl Harbor BB; Yankee Modelworks - onesie-twosie, Iron Shipwright - ditto; Ships & Co - USN Postwar, Admiralty Modelworks - RN 'tween wars; Loose Cannon - USN & RN oddball stuff