Additionally, when Josephine Brooks did the workshop in our membership on building a sales funnel, she did touch on lead magnets as well. This workshop will also be helpful if you're planning to tackle Quests 41 & 42.
You don't HAVE to have a lead magnet - it's not essential. Some people just share what they're going to be talking about in their next email via their social channels and get sign-ups that way. Personally, I did that for a long time. If you're not sure whether or not a lead magnet is right for you, I'd also point you to another workshop we have in FBCTV called Uncommon Email. This is a non-traditional approach to email newsletters and might resonate more deeply with you.