1) Arcades like Schneider Trading Associates, Marex Spectron, Xconnect, etc, which will provide you with exchange connectivity and leverage (depending on your success) as long as you bring your own money along.
2) Firms like Tower Trading or Met Trader (there are more), which will train you (sometimes the training is of questionable quality), but won't pay you a salary unless you are making money.
3) Investment banks will always be hiring a few people here and there for their dwindling trading floors.
There may be overlap between 1) and 2). The ones I mention are just examples that came to mind. If you look around these boards here, you'll find more. Beware of firms charging you for trading courses.