A good place to start is HealthCare.gov. This is the health insurance exchange created by the The Patient Protection and Affordable Care Act, and is a one-stop shop for private individual market health insurance plans (note that the exchange itself is run by the government, but the health plans for sale in the exchange are all private, from the health insurance companies with which you're already familiar). People in 39 states use HealthCare.gov to enroll in individual market plans. The other 11 states and the District of Columbia have state-run exchanges, and you'll be directed to their sites from HealthCare.gov when you select your state.
According to a Kaiser Family Foundation analysis, in 2018, the average American worker with employer-sponsored health insurance contributed $1,186 for a single employee health plan and $5,547 for a family health plan. Since this is an average, some employees may be paying much more (employers paid the bulk of the total premiums, which averaged $6,896 for single employees and $19,616 for family coverage).
For some consumers, buying individual health insurance is the only health coverage option. However, even if you have health insurance from your employer, an individual/family health insurance policy may still be an option to save money. With health insurance premiums increasing every year and employers passing more of the costs onto their employees, your company's health insurance may not be the best deal, especially if you need to cover a family.