Would you kindly add some of them, maybe with a short reasoning, maybe just for season 1?
Working off of
this list I would say:
S1: There's still a lot of important stuff in S1 that you can't really skip over. But:
1x04 is just a personal favourite, but you can skip that
1x05 if you really need to trim the fat, standalone mostly
1x12 is skippable
1x16
1x18 both are fairly standalone episodes
First seven episodes are a pretty important first arc, and the rest to 1x13 are equally important or introduce wrinkles to the show's formula. Also anything not listed you get a lot of character backstory from the stuff you watch, especially through flashbacks. Most of the episodes in S1 are procedural first, with a lot of serial lines simmering in the background, but they pave the way for when later seasons become more devoted to the serial arcs and all the small details start to pay off in dividends. The last stretch of 5 or so episodes ramps up the finale, so don't skip any of those.
S2: A few episodes got bumped up to required after some of the stuff in S4. You can't really skip a lot of S2 either, really, because most of the time you'll get really important season-long plot beats or big character backstory in them. Or quite a few middle of the road S2 episodes are full-steam serial instead of it simmering in the background.
The only ones in S2 you can skip for being mostly standalone are:
2x04
2x07 (though a really fun episode you should watch)
2x09
2x17
2x18
My list is heavily biased on episodes with significant character backstory or big season-length plot points show big movement. Most of these skippable episodes still have those longer plot points that they touch on, but usually not too big movements.
Honestly the list of what you can reasonably skip and still have a good grasp is really short that you should just watch it all.