Not too sure about Fortune, but what I feel like is the standard Squigly set (Silver Chord, Drag n' Bite, Battle Opera, Drag n' Drop and Inferno of Leviathan) has served very well on my Bio. As others have explained the basic combos I won't go into them, but I do like running both Chord and Drag n' Bite, and using whichever the situation calls for.
I mainly try to use Drag n' Bite against enemies that gain Unflinching on hit, like Untouchable or Armed Forces. The way Unflinching currently works in this game, enemies will still sort of stutter if you hit them fast enough after they gain unflinching mid-combo. If they gain Unflinching during my combo, it's usually enough to finish the combo and go into DnB. The opponent will not move back as far when hit with Unflinching in this instance, allowing me to close the distance and go into Drag n' Drop reliably after another L5. Outside of that, if you need more damage and are confident in how close you are to the opponent, DnB is a good option as well. Some situations (I've mainly found it when blocking a Cerebella's sweep attack and dashing in too quickly) will cause you to start your combo too far away, meaning the first hit of Drag n' Drop, or maybe even your launcher, will miss, so be careful there.
Under usual situations, Silver Chord is preferred if possible, especially for Bio. It will bring your opponent into range of Bio's Drain, and will allow Drag n' Drop to hit consistently for more damage and Armor Break.
