This is my standard block for 5e. Section headings are bold but the forums strip that. I'm lazy so only restored it for the first one. First one has Dex and Int saves included to show that as well.
Black Brotherhood Killer: AC 17; HP 97 (15d8+30);
Spd 30ft;
Melee rapier (+8, 1d8+5 piercing), slam (+8, 1d6+5 bludgeoning);
Ranged hand crossbow (+8, 30/120ft, 1d6+5 piercing plus 3d6 poison, DC 11 Con half);
SA cunning action, multiattack (melee x2), sneak attack +4d6, surprise attack (during 1st round surprise, extra 3d6);
Immune charm;
Str +0,
Dex +5 (+8),
Con +2,
Int +0 (+3),
Wis +1,
Cha +2;
Skills Deception +8, Insight +4, Intimidation +5, Perception +7, Sleight of Hand +8, Stealth +11;
Senses darkvision 60ft;
Traits ambusher, assassinate, evasion, expertise, read thoughts, shapechanger, uncanny dodge;
AL NE;
CR 6 (2300 XP).
Gear: studded leather armor, rapier, hand crossbow, 10 bolts poisoned with serpent venom, thieves’ tools, disguise kit, poisoner’s kit, 2 potions of invisibility, 10x10gp
Centaur: AC 12; HP 45 (6d10+12); Spd 50ft; Melee pike (+6, 10ft, 1d10+4 piercing), hooves (+6, 2d6+4 bludgeoning); Ranged longbow (+4, 150ft/600ft, 1d8+2 piercing); SA charge (30ft to target, pike attack, extra 3d6 piercing), multiattack (pike, hooves or longbow x2); Str +4, Dex +2, Con +2, Int –1, Wis +1, Cha +0; Skills Athletics +6, Perception +3, Survival +3; AL NG; CR 2 (450 XP).
Drow Lieutenant: AC 12 (15 with mage armor); HP 45 (10d8); Spd 30ft; Melee dagger (+5, 1d4+5 piercing plus 1d6 poison); SA innate spells (Cha, DC 12), summon demon (1/ day, quasit or shadow demon, 50%), spells (10th, Int, DC 14, +6); Str –1, Dex +2, Con +0, Int +3, Wis +1, Cha +1; Skills Arcana +6, Deception +5, Perception +4, Stealth +5; Senses darkvision 120ft; Traits fey ancestry, sunlight sensitivity; AL NE; CR 7 (2900 XP).
Innate Spells: at will—dancing lights; 1/day—darkness, faerie fire, levitate (self only) Spells (slots): 0 (at will)—mage hand, minor illusion, poison spray, ray of frost; 1st (4)—mage armor, magic missile, shield, witch bolt; 2nd (3)—alter self, misty step, web; 3rd (3)—fly, lightning bolt; 4th (3)—black tentacles, greater invisibility; 5th (2)—cloudkill
Gear: dagger, cloak of elvenkind, spell component pouch, spellbook