Here is a half constructed one.
Red Dragon Adept
AC: 16 (unarmored)
Resists: Fire
Elemental Affinity: Fire spells deal +3 damage.
Empowered Casting: The Dragon Adept may reroll up to 3 spell damage dice.
Metamagic: For each spell, the Dragon Adept may choose one of the following:
Quickened Spell: The Dragon Adept may cast a spell as a bonus action if they did not cast one as an Action.
Subtle Spell: The spell is cast without verbal or somatic components
Heighten: One creature has disadvantage on its first saving thow against the spell.
Spells: Slots 4 3 3 3 2 1
Cantrip: Fire Bolt: +6 vs AC, 3d10+3 damage
Spells Known:
Shield (1), Absorb Elements (1)
Hold Person (2), Misty Step (2), Scorching Ray (2), See Invisibility(2)
Counterspell (3), Fireball (3), Blink (3)
Wall of Fire (4), Greater Invisibility (4)
Circle of Death (6)
"Base" Strat: (for balance purposes)
Quickened L 5 Hold Person (4 targets) (75 pseudo-damage), twinned Fire Bolt (26 damage)
Quickened L 6 Fireball (11d6+3) (83 damage), twinned Fire Bolt (26 damage)
Quickened L 5 Scorching Ray (2d6+3 * 6 = 60 damage), twinned Fire Bolt (26 damage)
8 Strength (-1)
16 Dex (+3)
16 Con (+3)
8 Int (-1)
12 Wis (+1)
16 Charisma (+3)
Saves: +7 Charisma, +7 Constitution
Spell Attack: +7
Save DC: 15
Total: a bit under 100 DPR (offensive CR 15; attack bonus is 1 under, save DC is 3 under, so actually CR 14)
11d8+33 + 12 HP = 95 HP (CR 2)
AC is 21 with shield, so 8 high (CR 6)
Total CR: 10
Nastier tricks: Pre-buff with greater invisibility and blink and engage. Have allies trap them and wall of fire.
Each turn, reaction choices are shield, counterspell or absorb elements. Pick one that seems appropriate. Balance assumes constant shield use.