So here is my Warlock. Not quite a totally D20 cut and paste. Perhaps a bit too powerful? Lack of game balance? I never saw game balance as a problem I always saw players making dumb decisions trying to fight enemies head on with no strategy as the problem.
One who has made a pact with dark forces for great power. With this pact they are allowed great power with very little variety but they can use their magic unlimited times per day.
Armor: Ring mail or less.
Weapons: Warlocks prefer any simple type weapons such as short swords, rapiers, spears, staves and daggers. Not that it matters as Warlocks are sorry fighters.
Hit Points: 6 +1d6 a level
Natural 20: On a natural 20 the Warlock may gain half the damage done to his own hit points.
A warlock can use his Dexterity to dodge and flip with acrobatic precision as long as he does not have any Armor past +3. He use his Constitution to resist having his Invocations messed up.
Eldrich Blast based on Charisma. Range is Charisma + Level.
Damage is 1d8 from 1st to 4th level, 1d10 from levels 5th to 8th, 1d12 from 9th to 10th, And finally 1d20 from on up.
The get Invocations that they can always use.
Least 1 Every 4 levels.
Lesser at 5th level then every 4 levels.
Greater at 9th level then every 4 levels
Dark at 11th level then every 4 levels.
Dark Charm gives +2 to Charisma.
Dark Luck gives Charisma Bonus to all saves.
Darkness gives -4 to hit to enemies in Charisma radius in feet.
Dark Sight can see in darkness 60 feet.
Drain Blast adds Slowing effect to Eldrich Blast.
Demon Spear doubles Eldrich Blast Range.
Fright Blast add Fear to Eldrich Blast.
Dark Strike adds Eldrich Blast damage to weapon strike.
Devil's Jump adds Charisma bonus + level to jump distance.
Seer of the Dark can see the invisible.
Vamper Touch damages for 1d6 but give the Warlock 1d6 healing.
Shadow Blast adds Darkness to Eldrich Blast.
Hellfire Blast adds fire to Eldrich Blast 1d6 a round save ends.
Devil Charm +4 to Charisma.
Despair gives -2 to everyone in Charisma + level area.
Chain Blast hits multiple opponents in a row equal to Charisma Bonus plus level.
Devil Run mean the Warlock has double the movement.
Cold Hell Blast does an extra 1d6 damage.
Dead Minion summons minor undead equal to Charisma bonus plus Level.
Cut Ties Blast does damage and save or ends any magical effect if no save is made.
Dark Walk means invisibility at will.
Confusing Blast confuses enemies.
Tentacles and Thorns in Charisma in feet. All take 1d12 in the tentacles and thorns.
Spealleater ends spell of lower caster and heals 2 hit points per level of caster.
Dark Whirlwind Blast makes conical blast 10 feet plus Charisma bonus wide.
Plague Blast does 1d12 a round save ends.
Demon Acid Blast does 1d10 a round and takes away magical enchantment.
Hellfire Barrier does 1d6 per level and is Charisma in feet long.
Hell's Armor stops damage equal to level unless magic is used.
Out of the God's Sight is invisibility but is dispelled there is a blast in Charisma radius that does 1d6 a level.
Wraith Drain Touch damages 1d6 levels and gives that much in healing.
Demon Form allows the warlock to change into a Demon.
Human Warlock Teh Darada
Teh Darda was a weak sniveling yet very good looking young man. He always used his charms and good looks to worm his way into the noble circles where he knew they were practicing magics of great power. He unfortunately found what he was looking for as the nobility were Warlocks and has made a pact with a 30,000 year old demon named Kythiusis. He now has all the power but must forfeit his soul when he dies to the demon.
Str 5 -2
Dex 14 +1
Con 11 -
Int 7 -1
Wis 9 -
Cha 18 +3
Hit Points 9 (6 + 1d6=3)
Eldrich Blast +3 1d10+3 a round. Range 19.
Invocation Devils Jump +4 Feet
Flint and Steel
50 ft Rope