Which would be best for discus? And what about vinegar eels?For the baby brine shrimp (BBS), start with watching a youtube video (or two or three) of DIY baby brine shrimp hatcheries. They are really easy to make. And then hop online and order some BBS eggs and aquarium salt.
I don't know how to do blood worms. I've never seen people talk about blood worm cultures. But with the white worms (aka micro worms) you can buy a starter culture like you mentioned.
Me personally, I found another local hobbyist on facebook who was kind enough to make a microworm culture for me using one of his cultures. I found him by doing a shout out on a local aquarium club facebook page.