I'm looking for a novel with the usual fantasy setting where the MC doesn't have a grand goal, he just does his job at the adventurer's guild as an adventurer( a bit like chapter 18-21 of "I Said Make My Abilities Average!" if you don't really know), it doesn't have to be the whole LN but has to have fair bit of it. I'm also looking for a novel where the MC is an assassin or does a lot of stealthy action. I don't care if the protagonist is female or a monster, and I'd rather the MC not have a huge harem like in Death March.
hmm MC with no grand goal? i think you should search novels under Slice of Life tag. Assassin Landlord & Beauty Tenants Otherworldly Evil Monarch
you can try:Boundary Labyrinth and the Foreign Magician also there is Summoned Slaughterer with massacre friendly MC. Reincarnation ~ From the Upper World to the Lower World
Other World Assassin Life of a Man who was a Shut-in Havent actually read it much, just on my RL Does say it has harem though
How about an MC that does nothing.... but sleep? Try The Lazy King (Doesn't 100% fit the criteria) Imo for you, I suggest Running Away From The Hero.
The Man Picked up by the Gods. A man just doing guild's missions and sometimes gods' errands but mostly doing researches
Kuma Kuma Kuma Bear Female MC, main (only) goal: get delicious food and have a nice life (no saving the world / no hunting demon lords)
Magi Craft Meister? MC is just teleporting around the world through magic gates or something and being intertwined with multiple stories. Mostly involving his abilities as a magic craftsman(Magi Craft Meister).
Lazy Dungeon Master Outrageous / Ridiculous skill something something. Not really a lot of chapters translated, but boy does he later do what you're interested in.
＜Infinite Dendrogram＞ A Certain Middle-Aged Man’s VRMMO Activity Log Konjiki no Word Master I’m a NEET but when I went to Hello Work I got taken to another world Reincarnation ~ From the Upper World to the Lower World
For stealth/assassin: Otherworldly Evil Monarch The Nine Cauldrons Tales of Demons and Gods - MC had some stealth type beast transformation or something like that if I recall correctly
There's also Only Sense Online - vrmmo, with quests, crafting, etc. So what if it's an RPG world? - Loads of frenetic adventuring without a clear goal. Everyone Else is a Returnee - Set on Earth-turned-monsterland with angles angels. Dungeons, crafting, and a lot of genre savvyness.
MC w/ no goal? Aside from Kuma Bear, then maybe Tensei Shite Inaka de Slowlife wo Okuritai would fit your like