Here's a list of companies (not counting HnB heating non-combustion/cryogenic tobacco), in alphabetical order:
American Vapor LLC.
Black Mountain Fulfillment LLC.
Boulder International, Inc., -- platinum international
ECS Global LLC.
Fontem USA Inc /Imperial Tobacco (Blu); -- Blu, part of imperial tobacco
Mr. Juul Labs, Inc.; -- the famous JUUL
Kretek International, Inc.,
Logic Technology Development, LLC/Japan Tobacco; "-- Logic, Japan tobacco
Magellan Technology Inc.
Myle Vape Inc.;
Phillip Morris International, Inc. (MarkTen); -- MarkTen, owned by Philip morris
Reynolds American Inc./British American Tobacco(Vuse); -- Vuse, owned by Renault/British American tobacco
Vertigo Vapor LLC.
VMR Products LLC.
There are some familiar names on the list, such as JUUL, which currently has the largest share of the U.S. e-cigarette market, Blu of imperial tobacco, and Logic of Japanese tobacco. Philip morris' MarkTen did not start well, but it has a place thanks to the parent company's strong channel strength. Renault/British American tobacco's e-cigarette brand, Vuse, is mid-to-high. Boulder international, which has a strong market share in the Midwest, has also recently begun to make inroads in China.
This is the case in the U.S. home market, excluding other countries. The data is only for e-cigarettes that use the oil. Heat does not burn tobacco, including iQOS.