I always laugh at Eminence in Shadow. I originally read it as a Web Novel ages ago. The LNs have since diverged and gone past where the WN was, but I still crack up at Cid shenanigans. Volume 6 isn't out yet as an official translation, but I was dying when reading even an MTL version. I don't know why, but I love chuuni characters, and Cid is just the ultimate chuuni.

To be honest, lightnovels don't make me laugh all that often. I assume that is because of the slow delivery (limited by my reading speed) compared to anime for example. So I'm mostly grinning stupidly or in rare cases chuckling a bit when reading a funny book.

The series that makes me grin and chuckle the most, though, is Tearmoon Empire. Volumes 1-9 were translated in such a witty manner that there are parts that I unironically compare to Terry Pratchett's prose -not consistently, but the moments were there. Sadly the magic is gone now after a translator switch, but I don't want to get started on that again.

The Villainess is an SS+ Rank Adventurer.

Easily one of the best LN series I've read on Kindle Unlimited with plenty of genuine laugh out loud moments. I love going back through my highlights to see all the funny shenanigans.

The premise is the kingdom is in trouble so the 3rd princess sets off to solve everything because otherwise she won't be able to continue her lazy royal lifestyle.

Honestly any attempt I make to describe the jokes just won't do it justice. The dialog is extremely witty, the protagonist is OP but doesn't realize it, everyone else in the kingdom is useless, the deutagonist is silly... it just meshes together so well.

I will say that the first book of the series is the weakest one but after that, omg is it wonderful.