Three flavours of sidequest; Fetch. Talk. Kill.
Those are three pretty broad categories that a great many quests in video games seem to fall into, regardless of which game (though to be fair it’s generally an RPG issue, there’s not many quests in shoot-‘em-ups). The fact that nearly every quest (I won’t say definitively say every because guaranteeing that feels like a fool’s errand) fits into one of those 3 types is part of the reason a lot of RPGs feel grindy, or more specifically, the fact that they are obviously one of them. The fact that a quest is one of these doesn’t make it a grind, rewarding people for completing the quests (and I mean outside of a new gun or some experience) goes a long way in turning another go-here-do-this quest into something memorable and exciting. The failure to do so is a big reason why they become a grind.
One of the best ways to turn a quest like this into something better is to link it into part of a larger quest or event. Fallout New Vegas has a fair share of quests or quest chains that lead to bigger set pieces or additional help in the final battle of the game. A simple example (spoiler warning) is the Boomer quest chain, which is almost entirely talk-fetch-kill quests that don’t offer anything truly unique until the end where you get rewarded with a short cinematic-ish (at least for that game engine) spectacle, but it’s rewarding because it changes who’s allied with you during the final battle, in fact this can be said of multiple factions.
Another way is to make it directly provide a story or gameplay benefit. For example, in much of the Mass Effect series you can perform side quests to unlock additional companions, some of which you don’t have to obtain to finish the game. But in doing so it has an intriguing benefit to the player, that is, more squad mates to select from, and, more story—this makes it worthwhile and interesting for the player, even though some of these are just protracted kill quests.
Both of these take a lot of planning and are directly integrated into the main story, so how else can you make these quests memorable and enjoyable? The best way is to disguise what they are as best you can, for example by making them a special challenge, yes they might be a glorified kill quest, but if they’re interesting they can still serve as a fun side to the main quest. Assassin’s Creed’s fourth instalment does this with the legendary ships, four large and powerful ships in the corner of the map, each with their own special tactics. Defeating them is challenging and since it’s a far-away from the run-jump-stab gameplay of the main game, gives it a quality that makes it special compared to the rest of the game without needing any particular direct linkage to the main storyline.
Another way is to give it a special presence in the game, again I’m going to reference New Vegas here and That Lucky Old Sun, a quest to repair a power station. It is relatively straightforward as quests go, primarily being a fetch quest (though in this case you’re “fetching” a terminal/switch trough various stages of the quest), but it makes up for this with some fun dialogue and a nice flashy ending (along with potential weapon rewards depending on ow you complete it).
But one of the best ways (in my opinion) is really tight storytelling, because if you get it right, you barely need a quest at all. One of the best examples of this that I can think of is a ‘fetch’ quest that takes place in Fallout 3. The rewards from this unmarked quest in the form of items are good, recipes, a weapon, ammo. But you don’t know any of that exists when you’re finding the pieces of the story, and the story is what you’re really there for. Throughout the game you can find the tapes of an dysfunctional family trying to communicate with each other a plan to get into a bunker when the bombs fall. Each member has been given part of the code that their brother stole to access the bunker in part to try to force them to be together to ride out the apocalypse. Because this is an unmarked quest, the only reason to scour the wasteland looking for these tapes is to find out what happened to the family, not because you’re being prompted to, but because you want to find out what happened to them. I think that’s the best thing one of these side quests can be, memorable and interesting enough to make you want to find out more.
Now I just have to ensure the quests I write for the mod are that interesting.