1.Vanilla mobs plus:
Pechs (from Thaumcraft, mostly find these in magical forest biomes, neutral)
Wisps (also Thaumcraft, mostly find these in magical biomes and around nodes iirc)
Backpack endermen (from backpacks, these are annoying and look almost identical to normal endermen except the backpack, see?)
Angry Zombie (thaumcraft, has more HP than normal zombles, drops brains)
Blue slimes (Tinkers construct)
plus nether mobs for which I have precisely no idea which mod adds them (i is can grammarz
)
Imps (passive)
Heatscar spiders + baby heatscar spiders
Nitro creepers
Various critters added by twilight forest you won't see unless you go there (including teh bosses).
A few little things like squirrels and little birds, I think those come from Dye Trees mod?
Plus the demon bosses from blood magic. But you need to actually perform the ritual to summon them, you won't actually find them hanging about in the world.
2. Too many forge fluids for me to remember them all, i'll have a look when i get in from work.