MechaTarrasque
Hero
I have gotten a lot more use of the NPC classes in the MM1 then I thought I would so, I would add my vote for more of them.
Some CR 8 and 9 elementals, but I prefer that they aren't just extra-large earth elementals; mixed elementals or 4e style controller-type and artillery-type Myrmidons to go with the melee types from PotA would be more interesting.
The Demodand/Gerheleths and Barghest seem like outsiders that are tailor made for 5e.
Linnorms or sea serpents.
I would like more fey and celestials, but I think this is an opportunity to reinvigorate them. Make fey more weird and scary, and celestials more purpose driven and a little less funny looking cleric/paladin/druid [in my ideal world, a new celestial should be an inspiration for a new spell or ability for a cleric/paladin, as a new fiend/fey/abberation should be for the warlock].
Some CR 8 and 9 elementals, but I prefer that they aren't just extra-large earth elementals; mixed elementals or 4e style controller-type and artillery-type Myrmidons to go with the melee types from PotA would be more interesting.
The Demodand/Gerheleths and Barghest seem like outsiders that are tailor made for 5e.
Linnorms or sea serpents.
I would like more fey and celestials, but I think this is an opportunity to reinvigorate them. Make fey more weird and scary, and celestials more purpose driven and a little less funny looking cleric/paladin/druid [in my ideal world, a new celestial should be an inspiration for a new spell or ability for a cleric/paladin, as a new fiend/fey/abberation should be for the warlock].