That already exists, it’s called “Infiltrator.” :snark:
Having just one skill would really open up pet gameplay so that people would be fine with taking unusual class choices (though skill points are super tight on most builds, so I don’t know how you’d be able to fit enough free points for the third option).
Fire Skeletons Apostate + Flame Touched nodes would be awesome for a nonconventional pet build, and would probably be able to fit the skill points in.
Diviner’s Pet Spellbinder just needs Devouring Swarm to get lulzy damage values.
Guardian of Death’s Gate Pet Death Knight with Bonds of Bysmiel.
A hybrid Blight Fiend / Poison caster Cabalist might be viable if you had Path of the Three.
You can finally make a Dracarris Pyromancer work, probably with just Briarthorn as stuff like Seal of Khonsar gives bonuses to Empowering Presence anyway.
Witching Hour might become a viable hybrid as well, maybe as a Deceiver with Raise Skeletons
For non-pet builds, adding item modifiers make the possibilities real crazy. How about DW Blaze Herald + Bonemonger Infiltrator with Smite. Or Upheaval of Balance Druid with Deadly Aim.