Well, there's Teflammar Shadowlord, which gives an ability (called Shadow Discorporation or something like that) that let's you ressurect automatically 2 days after you die. I think. (long time since I last played nightcrawler).
Also, an always-on regeneration - like war shaper fast healing- can do the trick, if only for dramatic purposes (get knocked to -5 HP and come back from the dead 3 rounds later). Combined with Hellreaver healing, you can't come back from dead, but always will come back from near death.