6. Lydia Rodarte-Quayle
Some of you may scratch your heads with this choice but I think it's absolutely possible. We know Madrigal had ties to ABQ thanks to Los Pollos Hermanos. We know Saul had clients in the past that undoubtedly were involved in the meth business in some capacity (before Walt and Jesse). I really don't think it's that much of a stretch to imagine the Stevia-addicted Methylamine supplier of the southwest having tea with Saul Goodman in the very same restaurant she conducted most of her illegal business. Go forth, writers and make it happen!
5. Gus Fring
The next logical character that could appear in several episodes would be none other than Gustavo "What the hell happened to the other side of my face?" Fring. He was a local business owner, a prominent member of the community, and ran an enormous drug empire. The need for a local lawyer that could look the other way was practically a necessity. It wouldn't surprise me in the slightest if Goodman had a more direct connection to Mr. Fring in the past.