Find something you know about and care about and work out how to solve people's problems.
There are literally 1000s of ways to make a profit because there are 1000s of unsolved problems.
I know a women, single mum, who makes money printing ribbons for the end of athletics races like marathons and such, and also makes printed sashes for birthday cakes and beauty contests. I gave her the running winners tape idea and how to sell it or market it to race directors. She sells about 300 dollars worth every week. The ribbons are made by a machine she bought. She sells the for 400% of the raw input costs
In a place the size of the US think how many schools cross country races there are, not to mention 5k, 10k, half marathon, marathon. There are literally 100 races per week, easily. Ribbons are light and easy and cheap to post.
If you were organising a race how the heck would you go about making a 4 meter long ribbon with printed writing on it? If you can buy one for 15 buck why wouldn't you. It looks cool in the pictures and makes the race look professional and that is what makes runners sign up next year.
Or what about all the parents of children who need spiked running shoes for racing, wear them once and the child grows out of them. Or ice skates. Specialise in good quality second hand sports equipment.
I cannot tell you what business to run because I don't know where you passion lies. What problems would you like to solve?