Hi folks, I'm looking to run a game with folks interested in whimsical and silly style of play, I think everyone is planning on playing Gnomes or other smol characters, so anything with those vibes would be great.

Thanks in advance!

It might not be the most whimsical campain but it definitely fits and since you specified 3.5e (which I interpreted as somewhat old-shool), I would like to recommend Dolmenwood.

Is is built for OSE but it is closer to 3.5 than any content for 5e, so easily adaptable.
It is a whole world with an hex-map filled with adventures and a few campains are provided. It takes place in a giant wood-land with some fey-wild shortcuts and has a good dose of whimsy (talking mushroom folks and the like)

I recommend you give it a look, I don't know if it is the right fit for you but if it is, you have year of adventures ahead of you, ready in a book.

For a different take on 'whimsical', take a look at Toon from SJGames.
https://www.sjgames.com/toon/

There is a cute one where this gentleman named Strahd invites you over for a dinner party and hijinks ensue.

Does it have to be DnD? Honey Heist came to my mind