The numbered books tend to only have anything resembling continuity if the same author is involved. Peter David and John Vornholt come immediately to mind as ones to do that.
A Stitch in Time (By Garak’s actor) also gets referenced, but that book is an extra special case in the franchise.
Outside of the authors referencing their own work, sometimes New Frontier gets referenced: mostly in the form of Zak Kebron (The BEST character to ever happen to Trek) being Worf’s old academy roommate, or in the form of a major disaster hitting the entire quadrant and you get little cuts to various ships…