In the darkest days of HealthCare.gov's dysfunction, I was preoccupied for a time by the partial workarounds enabled by third-party informational sites like ValuePenguin and HealthSherpa. ValuePenguin in particular offered (and still offers) a near-complete and accurate substitute for the informational functions of HealthCare.gov: it will calculate your subsidy and show you all available plans, accurately priced, with plan summaries.
HealthCare.gov at first, famously, had no pre sign-in informational feature allowing users to scope out options if they could not register, as most couldn't. When that feature was hurriedly added, it at first referred people to the Kaiser subsidy calculator, rather than incorporating its own subsidy calculation. It also gave out misinformation, at least for me in New Jersey: failing to query about age, the site quoted prices at a middle-range age without disclosing that it was doing so. In my case, the quoted prices were half to two-thirds of the actual prices, which I found on ValuePenguin and confirmed with the insurers.