Kylington has the highest potential, and would love to re-sign him. Of the rest, Lindholm, Tanev, Zad, and Backlund would be the only ones I'd go for, if it was reasonable. Zad has honestly been my third favourite D the last couple years (Rasmus and Tanev are first and second). Tanev if he's willing to accept less and primarily be a PK/third pairing guy (rather than top 4 guy), would absolutely take him back.