Working capital, in this case you get 25K. I do a lot of option spreads which require a lot of capital but have small returns.
Like let's say you do a spread for 250, and the return is $10, you are risking 250 to get 10 which on the surface seems like a waste but the chances of it winning are 90 percent
But if you do the trade with 25k you would be risking 25k to get 1000 with 90 percent chance of winning
But to answer your question generally, most people use prop firms to trade futures, futures require a lot of capital that most people don't have
The link I posted is one that does options, it's the only one as far as I know, I think a lot of people here do options so somebody should find it interesting