Pofire
To go ahead and start off a pofire list,
The mobs in the field near zone in do not summon. However, the named spider can spawn in the field and does summon.
The lava lordlings/mephits that path in front of the castle on the other side of the lava river do not summon.
To my experience, none of the mephits summon and the only place caster mephits spawn is on the mephit isles.
The mobs in the field after castle 1 all summon as far as I remember. After that field you go into the second castle where none of the mobs summon except for named mobs. However, there are many casters and bards should stick to soloing the area with the tables as all the mobs spawning in there are warriors and do not cast.
That's about as good as it gets for pofire.