Ya, I have been playing a ton of 5e lately? Why do you ask? Here is some more ideas for your 5e game-Lich patron Warlock?
Power comes when things die. What kind of power can come from something that refuses to die? You’ve meet the creature in its tomb lair. It offered you power along side its smell of decay. You said yes. Now you do the bidding of the cadaver itself.
Lich Expanded Spell List
1st inflict wounds, protection from good and evil
2nd phantasmal force, blindness/deafness
3rd animate dead, protection from energy
4th Phantasmal Killer, evard’s black ttentacles
5th cloudkill, mass inflict wounds
Starting at 1st level, you patron bestows upon you the speech of the dead. As an action, you can cast speak with dead. You can’t use this feature again until you finish a short or long rest.
Life Draining Touch
Starting at 6th Level, your patron teaches you the secret of draining the life of others. When you at the subject of a melee attack, you can cast vampiric touch as a reaction to the attack. You can’t use this feature again until you finish a short or long rest.
Command of the Dead
Starting at 10th level, unintelligent undead will not longer attack you. In addition to you gain resistance to all damage dealt to you from all undead, intelligent or otherwise.
Also, at 10th level, you gain the bonus spell create undead once per day.
Wrath of the Lich
Starting at level 14, you can point at a creature and fire a beam of negative energy at it as an action that can be avoided with a charisma saving . If you succeed, you inflict 5d8 necrotic damage on the creature and the paralyzed. You heal half the amount of damage dealt. Each turn the creature can make a saving throw at the start of its turns. If it fails it continues to be paralyzed and take 5d8 necrotic damage, and you continue to heal half the damage dealt.
You can not do this again until you complete a long rest.