kigmatzomat
Legend
My general take is that crafting a magic item should always involve questing for components. It should never be as simple as insert gold, get magic item. So whether it's a specific ore only found in a section of the Underdark, or the feather of an albino harpy, creating a magic item should always drive adventures.
We tend to do it backwards. "Well, we killed an albino harpy, two mind flayers, a mess of oozes and slimes plus we found that weird metal that casts no shadow in dim light but casts two shadows in bright light. What can we make with this?" "Hrmmm, with materials we can easily collect or buy, I think we could figure out a cloak of displacement, ring of mind shielding, a helm of telepathy or an ioun stone of Intellect."
Which is not to say we never quest for enchanting supplies. Just not frequently.
Our gm has one of the vague formula systems that reduces materials to kinds of mystic "essences". I.e. a red dragon has fire essence, life essence and evil essence. It's heart has the most life, it's eyes the most evil, the tongue the most fire, but there's some in all of it, at least on older dragons. Giants have strength, windlings speed, etc, etc. There's a couple of guidelines for how many total essences of how many types should be used based on either rarity or a magic item value tables, plus advice to require "thematically appropriate" sources.
There are also rules for using extra potent materials to make things easier. Kind of like using a chunk of uranium to make a flashlight that won't go out for 9 million years. It's super easy to make but also kind of a waste.
E.g. We fought a kraken, an aboleth plus some weird franken-squid aboleth constructs. All of them were just full of tentacles, poison, grappling and magic essences so we were able to easily make a grappling/poisoning whip ("poison strand" from a kobold press book) for the monk. Using poisonous, grappling, whip-like material components that have twice as much essence as needed and are almost insanely thematically appropriate meant we could make the whip without having an explicit formula and have a DC that was something sane (at least for a party with two bards with Expertise(Arcana) and a cleric with enough spell slots to keep them both under Enhance Attribute all day)