For getting stains out of fabrics, I haven't found anything that works better than rubbing a regular bar of soap directly on the stain (and then agitating it with my fingertips/fingernails, rinsing with cool water, and repeating on the other side).
There’s actually an ancient laundry stain remover that’s in bar form called “Fels-Naptha” (which is usually $0.99 but in 2022 suddenly spiked in price) I use it for laundry stains now, but I spent decades using whatever bar of soap happened to be in the shower, and that worked great.
As a woman, this has really relieved one of the stressors from 'that-time-of-the-month.'
Remember with blood to always use cold water.
And remember not to dry things in the dryer until you’re sure the stain has been removed, so that you don’t inadvertently set it.
(Consumer Reports rates the OxiClean Maxforce spray as their best laundry stain remover, so I keep some on hand as well — it’s a little less work for giving the armpits of gym clothes a regular once-over. Generally cheapest at Walmart.)
(And for laundry that is a little smelly—gym clothes, socks, or a towel that maybe hasn’t dried out quickly enough, I’ve been impressed by Lysol’s laundry sanitizer additive. The free & clear unscented one can be hard to find, but they’ve recently had it in stock again at Target. I also switched to a waffle-weave quick-drying towel that I love from Onsen — it’s expensive but I really just need the one 🤷♀️)