I’m just gonna… San’layn/vampyr elf Customization (and Allied Race idea) Coagulated Megathread {Re-VAMPed}
I’d love San’layn for an AR, obviously. That’d be a perfect undead AR for me 
Vampyr and blood magic all the way. Take a look at the megathread if you want to see an AR concept that has a ton of work and concepts put into it from its community for ideas.
As for Lightforged undead, that’s one I really am against. Despise the concept and sincerely hope it never comes to be.