Example of using PlayerDeathEvent#getItemsToKeep

Listener.java

    @EventHandler(ignoreCancelled = true)
    public void onPlayerDeath(PlayerDeathEvent event) {
        for (Iterator<ItemStack> iterator = event.getDrops().iterator(); iterator.hasNext(); ) {
            ItemStack drop = iterator.next();
            List<String> lore = drop.getLore();
            if (lore != null && !lore.isEmpty()) {
                if (lore.get(0).contains("(SOULBOUND)")) {
                    iterator.remove();
                    event.getItemsToKeep().add(drop);
                }
            }
        }
    }