A very common type of quest in RPGs is a scavenger hunt: go get these three (or four, or five, or ten) things. For example, the heroes might have to go get four kinds of herbs for a poultice, or bring back the heads of five different monsters. I'm developing an adventure right now that has the heroes collecting bugs; in an adventure I recently developed, they need to get parts of a magical key. There are lots of things to go look for, but the general trend is "go get these things then come back here."

The biggest advantage of a scavenger hunt is that the players can go get the items in whatever order they want. There's freedom to roam, and that increases player agency. The downside is that fetching multiples of the same kind of thing can get really repetitive. If you have to collect four herbs and need to make a Nature check to harvest each one, the third and fourth time feels really same-y. If you have to bring back the heads of four giants, fighting four of the same kind of giant can seem tedious. The most typical (and probably worst) example is when the heroes have to just find the things, resulting in a bunch of Perception checks. Heroes make Perception checks all the time; more of them to complete a quest doesn't feel thrilling.

The key, then, is variety. Each task of the scavenger hunt should be different and test different abilities, even though they're initially presented as similar. Here are some suggestions to make a scavenger-hunt structure seem a little more exciting.

* Only One Check To Do The Thing. If you have the heroes picking berries or collecting favors from nobles, they might expect a bunch of Nature checks or Diplomacy checks or whatever. That's fine. You should play into the expectations, but only once. Only one of the berry types is concealed by foliage or similar-looking-but-not-right berries and requires a Nature check to collect; the other berries should all have different challenges other than the Nature check. Similarly, only one noble should need convincing via a Diplomacy check; the other nobles should require different challenges to earn their favors. 

* Unexpected Skill Checks. Think about how to make another kind of skill check unexpectedly relevant. Perhaps one of the berries is deep inside a thicket and requires a Thievery check to pluck it without taking damage; this lets the party rogue shine for a moment. Perhaps a noble has been posed a vexing riddle and wants help to solve it before granting her favor. An Arcana or Intelligence check (or, better yet, posing an actual riddle to the table) lets smart-but-not-charismatic characters feel useful. Maybe one of the giants the heroes have to kill is already dead, but vermin are feasting upon the body and the heroes must shoo them away with a successful Nature check, or preserve the head with a successful Medicine check.

* A Hidden Order. One of the scavenger hunt items might be impossible: the thing they're looking for just isn't there, or is currently inaccessible. Only once they've gotten a different item does the impossible item "unlock." Maybe one of the nobles doesn't want to talk at all until the heroes have earned the favor of his best friend, one of the other nobles. Then the heroes can come back. This creates a satisfying interconnectedness to the tasks and makes the whole scavenger hunt seem less like a bunch of scattered, unrelated things.

* A Fight! As RPGs have combat as a primary component, it's not a bad idea to lean into that even in a scavenger hunt. At least one (or more!) scavenger hunt item should include a fight, and an unexpected fight is the best kind. Maybe one of the nobles has been challenged by a rival and needs the heroes to serve as his champions against the rival's champion, a minotaur gladiator. One of the herbs might be in the domain of a malicious fey creature that's spoiling for a fight. Inventing combats to throw in isn't hard.

* Not Really a Fight. Slightly more challenging is something that seems like a fight--and maybe it can be confronted as a fight anyway--but there's a better way around it. Maybe the heroes can find out that the minotaur gladiator doesn't really want to fight, and will throw the fight against the heroes if they can make the bout look good with a successful Performance check. Perhaps the malicious fey can be mollified with a bauble the heroes found at a different herb site. It's always good to think about how heroes can avoid a combat they don't want to undertake, but put special consideration of that here.

* Build For A Little Failure. One important point is that your scavenger hunt shouldn't require complete success on all items; that's putting success behind a "skill wall" that not all parties can overcome. I prefer to make a baseline assumption that most parties will get all but one of the scavenger hunt items, and the adventure proceeds fine with that (of course, it also proceeds fine for completionist players who want to get every single thing). I'll often build in how the heroes can proceed if they get all but two (or even all but three) elements of the scavenger hunt. This usually makes progress harder, but it's still possible. Perhaps having only some, but not all, parts of the key does a lot of damage to the heroes when the magic door is opened. Maybe failing to get all the herbs means the poultice leaves some lingering negative effect for a while. The players should realize they can call the scavenger hunt quits at any time, but there might be a cost to them if they do.

Happy hunting!