For my game, Forsaken Alchemy (FA for short), I've got a loot system that's pretty simplistic to start but doesn't get me anywhere. I wanted to get rid of the RNG loot drop trope I've seen so many times in games.
Instead of relying on RNG Jesus, you get specific items from enemies by killing them a certain way, so you get what you earned 100%. For example, if you want some hair from this hairy enemy, that's not going to be there if you burn it to death, right? However, if you stab said enemy to death, you'd always be able to harvest its hair.
I'm not putting equipment or money as loot because in FA, all the equipment you need is handed to you early on, and there's this Replicator item that lets you duplicate most objects, so there'd be no point in having a currency system, in my opinion, if you could just replicate items infinitely and sell them.
Ok, I know for most RPG players out there, what I just said must sound shocking, but equipment in the game isn't like major stat modifying gear that's in Final Fantasy, Dragon Quest, any MMORPG out there, etc. You've got 3 sets of armor. Light, medium, and heavy. You can only equip up to 5 pieces from each set at a time. Light armor increases a stat called turn priority, which is one of two things that dictates who goes next in the turn order, but the trade-off is that you also take more damage. Heavy armor is the opposite, so you're slower but more defensive. Individual pieces of medium armor protect the character from debuffs. Each character has their unique, personal weapon, so there's no weapon upgrades out there. Accessories are also there for reducing damage taken of one element while increasing damage taken of another element as a trade-off. The only reason why I made equipment so simple is because I'd like minimalism to be one of the game's strong suits. Instead of having a hundred different armor pieces, accessories, and weapons that players collect throughout the game until finally getting gear that's completely superior to everything else, just give them all near the beginning, so they can experiment and learn what best fits the scenario, and there will be several situations where each piece of equipment is useful, so none will be forgettable.
As far as why you have a Replicator that duplicates most items, I have that to remove the need to grind/farm for items that'll be necessary for a lot of alchemy recipes to make battle items. It'll be balanced by having a strict space and weight limit per item per character, and the Replicator can't be used in battles. Also, everyone automatically gets healed after every battle, so there'd be no reason to replicate healing items to use over and over again outside of battle. I didn't want that to be a chore for players to constantly make new healing items right before using them after fights.
Anyway, now that you know why equipment and money aren't part of the loot system, and we're only getting enemy-related items, like that hair I mentioned at the beginning, where to go from here? I was thinking of having that be a completionist hunt for all the different types of loot, but then, what would be the purpose of doing that? Maybe have an optional cosmetics thing that uses loot? I don't wanna say I've written myself in a corner because I'm sure there's a viable answer out there that doesn't remove what I've already laid down.
Before you say, "Make quests that revolve around getting enemy-dropped items, so you kill enemies in specific ways to get said items," I'm not going to do that. That's just a twist on the trope of "Kill this enemy to get this item" that we see in so many games. Besides, even if I do make quests about that, what would be the reward for the player? I just talked about the lack of need for new equipment and money. The sidequests I do make for FA will have character relationship development rewards, and no, I won't make kill quests give that reward because that kind of thing is meant for sidequests that have a mystery conflict the player has to solve through gathering evidence and piecing them together alongside certain characters.
Before you say, "Make each loot item be an optional ingredient to make alchemy recipes stronger," I thought of that already, and I don't want players to think, "Look, a new enemy! Time to get all the different loot and see what they do to make alchemy stronger than usual." The reason why not is because, even though this is an RPG and RPGs usually have you kill a ton of random enemies to get leveled up in preparation for bosses, I'm not doing that. I'm giving the player alternate paths around random enemies, so it'd be possible to go boss to boss, and level ups aren't beneficial since enemies will level up with you. In fact, I made level ups more of an extra challenge for those that think the game's too easy. Of course I'll throw in a warning in-game, so players don't accidentally make their playthrough harder. That's not to say you should avoid all random enemies because I made it possible to still beat them but not get exp while getting all the different types of loot. The reason why random enemies are even a thing is learning practice for bosses since I have a very adaptive A.I. per enemy type, so players are always learning to train their responsiveness.