Getting any of the following might take 4 months+ depending on rng.
Some mini bosses have 9 spawn points, 6 or only 3 (because of 3 channels). Increase unique mini boss equips droprate as see fit.
Zeno (Glowing Whip) (I think 0 found)
Seruf (Frozen Tuna) (I think 1 found)
Faust (Fishing Pole) (I think 1 found)
Deo (Flaming Katana) (I think 2 found)
Timer (Heart Wand) (I think 4 found)
Stumpy (Frying Pan) (also drops from Cloud Fox)