Monster families in Diablo 4 have different drop rates for different types of gear. Could be useful to target farm certain pieces but it might be offset by the lack of density for certain mob types.
Heres an amazing list compiled by reddit user u/NightKrowe that lists which dungeons have which types of mobs to better help you target your farming:
Bandits ( Daggers, Maces )
Mournfield Faceless Shrine Calibel's Mine Renegade's Retreat Maulwood Maugan's Works Uldur's Cave Raethwind Wilds Light's Watch Luban's RestBeasts ( Chests, Crossbows, Swords )
Mournfield Haunted Refuge Uldur's Cave Leviathan's Maw Path of the Blind Fetid Mausoleum Akkhan's Grasp Corrupted Grotto Light's Refuge Blind Burrows Tomb of the Saints Demon's Wake Bastion of FaithCannibals ( 2H Axes, Axes, Helms )
Steadfast Barracks Pallid Delve Bloodsoaked Crag Earthen Wound Charnel House Guulrahn Slums Fallen Temple (Capstone) Faceless Shrine Bastion of FaithCultists ( Daggers, Helms )
Cultist Refuge Steadfast Barracks Buried Halls Inferno Leviathan's Maw Path of the Blind Faceless Shrine Serpent's Lair Halls of the Damned Dark Ravine Conclave Shadowed Plunge Yshari's Sanctum Heretics Asylum Endless GatesDrowned ( Scythes, 2H Maces, Pants, Boots )
Belfry Zakara Vault of The Forsaken Ghoa Ruins Ruins of Eridu Flooded Depths Corrupted Grotto Fetid Mausoleum Mariner's Refuge Akkhan's Grasp Putrid Aquifer Sunken Library Dead Man's Dredge Haunted RefugeFallen ( Axes, Staves )
Ruins of Eridu Demon's Wake Fallen Temple Capstone Grinning Labyrinth Oblivion Fading Echo Wretched Delve Ancient's Lament Shifting City Cathedral of Light (Capstone) Bloodsoaked Crag Endless Gates Whispering Pines Shivta Ruins Garan Hold Conclave Sirocco Caverns Caldera Gate Lost Archives Halls of the Damned Derelict Lodge Pallid Delve Mournfield Guulrahn Slums Onyx Hold Forgotten Depths Buried Halls Iron Hold Champion's DemiseGhosts ( Bows, Wands )
Haunted Refuge Lost Keep Forbidden City Buried Halls Sealed Archives Broken Bulwark Abandoned Mineworks Black Asylum Tomb of the Saints Iron Hold Crumbling Hekma Halls of the Damned Whispering Vault Onyx Hold Seaside Descent Immortal Emanation Earthen Wound Calibel's Mine Guulrahn Slums Sunken Ruins Mariner's Refuge Oblivion Lost Archives Twisted Hollow Stockades Maddux Watch Penitent CairnsGoatmen ( 2H Axes, Axes, 2H Staves, Totems )
Champion's Demise Forsaken Quarry Hoarfrost Demise Sepulcher of the Forsworn Komdor Temple Mercy's Reach Rimescar Caverns Oldstones Anica's Claim Domhainne Tunnels Shivta Ruins Broken BulwarkSkeletons ( Crossbows, Shields, Swords )
Forgotten Depths Betrayer's Row Mournfield Belfry Zakara Hakan's Refuge Komdor Temple Crumbling Hekma Defiled Catacomb Yshari's Sanctum Collapsed Vault Forgotten Ruins Sunken Library Ancient Reservoir Halls of the Damned Pallid Delve Zenith Demon's Wake Cathedral of Light (Capstone) Hoarfrost Demise Black Asylum Stockades Kor Dragan Barracks Nostrava Deepwood Seaside Descent Tormented Ruins Maddux Watch Crusaders' Cathedral Luban's Rest Garan Hold Underroot Caldera GateSnakes ( 2H Polearms, Swords )
Serpent's Lair Shadowed Plunge Witchwater Ghoa Ruins Forgotten Ruins Deserted Underpass Hakan's Refuge Putrid AquiferSpiders ( Chests, Focus, Gloves, 2H Swords )
Blind Burrows Hive Diablo Abandoned Mineworks Sirocco Caverns Witchwater Whispering Pines Deserted Underpass Guulrahn Canals Ferals' Den Defiled Catacomb Sarat's Lair Pallid Delve Oldstones Champion's DemiseVampires ( Bows, 2H Swords, Wands )
Akkhan's Grasp Dead Man's Dredge Forbidden City Fetid Mausoleum Immortal Emanation Kor Dragan Barracks Heathen's Zenith Sanguine Chapel Hallowed Ossuary Collapsed VaultKnights
Cathedral of Light (Capstone) Light's Refuge Lost Keep Maugan's Works Heretics Asylum Renegade's Retreat Prison of Caldeum Kor Valar Ramparts Bastion of Faith Heathen's Crusaders' Cathedral Mercy's Reach Broken Bulwark Light's WatchClerics
Lost Keep Light's Refuge Bastion of Faith Heathen'sOnce again all credit to reddit user u/NightKrowe for compiling this list