The only two that came to mind were these. In them Spike jumps, but he doesn't necessarily die or come back.
Love's Gift by PfeifferpackSummary: What if Buffy didn't take that dive off of the tower in The Gift? What if she saw Spike for the man he was becoming and spent the next year without the depression caused from her being pulled from heaven? Could they have progressed to love on a natural course. Begins at climax of The Gift then AU. Time Vortex by ImmortallySpuffySummary: Five ways that Spike travels back into season five. One portal and five potential outcomes. Written in response to a Fang Fetish/Darker Spike Challenge. Collab fic by: MaryPerk, JackofSpikes, Kargrif and Athenewolfe.In Time Vortex, it's Scenario 5 where Spike jumps.