This one's a fairly simple solution to a fairly common problem. The problem is that some PC wants to create a magic item, and you need a list of components that they need to collect to use as the raw materials for the item, and are sorely lacking in inspiration. If this doesn't happen to you for the first magic item the PCs create, I'm sure it happens by the third or fourth, as the number of clever literary examples you can draw on from memory starts to be exhausted. Here's how I handle generating components:
First, I roll 1d6+1. If the item is particularly powerful, I'll roll 2d6+2. This is the number of components a PC has to collect. Next, to generate the components, I use one or both of the following processes.
1) Roll on your wandering monster table once for each component. This will generate a monster and some item to be collected from them. You may have to interpret things slightly, especially if you were boring in generating tracks or lair-types for each monster. If you roll monster, choose their most prominent or grossest feature for collection. Even abstract or transient things are fine. If they have to collect the roar of an ooze attack-squad's jetpacks, that's their problem, not yours. For variety, I recommend splitting the rolls across multiple wandering monster tables if you have them, since this will encourage the PCs to visit various areas to collect them all. You may also want to roll 1d10 for the # of each thing a PC needs to collect (i.e. 6 mummy hearts or whatever), but I find this often leads to a boring grinding feeling unless the PCs can reasonably expect to find a group of the right monster type at once (alternately: present them with a clear idea of where to find such a group).
2) I use this second method when I want to include rare metals, gems, etc. as components instead of just monster bits. I start by taking a treasure generator like Courtney Campbell's Treasure and just rolling as if the components needed for the item were part of hoard being generated. I recommend keeping the numbers, so if the generator spits out 32 fire badger pelts, then they need 32 fire badger pelts. I try to swap out as much coinage as possible for items and commodities, but if some is left, that's fine - I take that to mean that much raw metal of the appropriate type is required. If you're in a particularly lazy mood, you can even just pick components off a previously generated treasure hoard that the PCs picked up somewhere else. In practice, this often comes across as masterful planning and foreshadowing instead of laziness, and it encourages them to track down the people they sold their previous treasure to, in order to get the item back.
Usually, I'll combine these two, with about half the components being generated treasure stuff, and half being monsters you have to kill. I find this mix tends to maximise the fun vs. complexity factor. The PCs can discover the items on list in whatever way you think appropriate - legend lore spells, consulting sages, you telling them directly to save time, whatever you'd like. I favour this method because it repurposes existing material prepared for the game (wandering monster tables, treasure hoards), but also generates relatively straightforward leads and goals ("Where can we find a flawless sapphire worth 5,500 GP?"). I recommend you try it and see how it works in your game.