Heading down the rabbit hole…
Qwikiverse maps the references between stories: what Better Call Saul nods to, and what nods back. How it works
https://teepublic.zendesk.com/hc/article_attachments/360049702254/bettercallsaul-logo.svg
Fair use
Nothing spotted here yet.
A line quoted, a cameo, a character named after something: if Better Call Saul nods to another story, or another story nods to it, spot the first one.