Jumping on this – Micro Four Thirds has a slew of super compact, light, tiny lenses.
If you want a standard zoom, I love the silly pancake-like Panasonic 12-32mm f3.5-5.6 kit zoom. Even though it lacks a focus ring, and is slow, it is tiny, and a superbly fun set of focal lengths for someone coming from decade old point-and-shoots. It weighs 70 grams and retracts to virtually nothing when not in use.
And there are other small lenses as well, the Olympus 45mm f1.8 is a shockingly diminutive portrait lens with nifty bokeh, and the manual focus only Laowa 7.5mm f2 is probably one of the smallest rectilinear ultrawide angels you can get.
(It’s fun over here!)