It's a hard choice to decide which item is best out of joy seed,reviver seed and friend bow, but i think reviver seed would be the best.
Reason- It is extremely useful if you are in a hard dungeon, especially if you have lots of them as it will be extremely hard to die in that dungeon(unless you are in a 99 floor dungeon).
What do you think is the best item? And if you think it is reviver seed, what do you think the second best item is?