I have a number, all good in various ways.
A tiny Decathlon job that almost permanently lives in my pocket. Small, windproof, shower proof and weighs nothing.
A slightly thicker, more waterproof, mesh backed Pearl Izumi thing that is my default spring/autumn top. Small enough to fit in a jersey pocket if needed.
A thicker again Giordana thing, less waterproof but much warmer, can fit in a pocket if pushed but it’s a bit bulky.
And some Rapha to finish, a freebie from Manchester to London, waterproof, very good protection but just a bit bulky. It’s my crap weather option.
As you can see, I do like a gilet.