I know you need to mix critters and monster parts to make elixirs, and that changing the critter changes the elixir. Does it matter which monster part you use, though? Is there any benefit to using more than one per elixir?
I've experimented a bit, and it doesn't seem to matter, but I've only tried the items I have a lot of. There are also no indications in the item descriptions that it makes any difference. I've googled a bit about elixirs, but I haven't found anything that explicitly says one way or the other.
Best Answer
This gallery has a pretty great breakdown of all the effects of all monster parts (and everything else) - generally speaking, most of them add duration, with shards of the dragon horns doing the best work at a whopping thirty minutes.
Adding several ingredients that have additional effects at higher "levels" will give a better bonus to food/elixirs. For example, three mighty bananas, a mighty thistle, and a shard of one of the dragon's horns will provide a +3 damage boost for thirty minutes.
Monster parts themselves do not appear to have much of an effect aside from duration increases (some dragon parts adding hearts notwithstanding).