Random idea:
An Elseworlds story where Year one Scarecrow becomes an anti-hero.
He’s not a member of the bat-family, but he works with them every so often. He starts as a straight-up villain at the beginning of the comic as usual, but after being defeated by Batman, having his fear toxin turned around on him kind of acts as a ‘wake up call’?
I came up with four separate scenarios and scenes that could take place in a universe like that. He almost becomes a red hood-like figure, but with fear toxin, snake venom, and crows. Lots of crows.
Might be a bit of a stretch but one of the ideas I had involved Karen moving to Gotham after the events of the comic. (Without her husband, she needed a job and a place to live, so she moved to some crap apartment with Jon’s sister. Everyone assumed Jon died, so she had no real worry about him popping up again.) Only to hear about this ‘Scarecrow’ running around and realizing she made a terrible mistake. Karen and Jon’s sister end up becoming reoccurring characters. (With, by the way, no incentive in the slightest for Jon to forgive her, in fact, it’s actually the opposite.)
In that type of scenario, a situation arises, as Karen gets into trouble with loan sharks and it results with Jon’s sister begin kidnapped. Jon finds out about this and saves her, maybe having some internal monologue about it, then returns her to Karen in person. (Basically to say ‘I’m not going to kill you anymore. Not because I don’t think you deserve it, but because Batman made me realize you’re not worth my time.’) Then he leaves.
This basically sums up how I imagine this type of story going. But honestly, that still could leave a lot of potential character relationships, scenarios, and other things open for possibilities.