Twilight Forest adds charms of keeping as loot that can be upgraded to preserve your held item, entire action bar, entire inventory.
Open Blocks has by default functionality that will place your items in a gravestone on death.
The gravestone mod will place your items in a gavestone on death - but includes worldgen (dungeons with an ender boss) and new mobs.
Undertaker places intems in a gravestone on death and looks like a potential lightweight alternative to OpenBlocks or Gravestone mod - you must carry an item to get this to happen.
Thaumic Tinkerer adds (added? I havn't used it in a while) an item that could be crafted and held to get a one shot gravestone like functionality.
Witchery I think might include a poppet that helps rescue your items on death.
I try not to use any of these mods except for Twilight Forest as they feel like a cheaty way of avoiding a base game mechanic, and collecting charms of keeping seems like enough work to validate the benefit of keeping my stuff.
