GM-5 is probably the greatest pocket-size mirrorless, and maybe the last. The GX-85 is also great, but it does have a larger grip and more of a shoulder at the top.
The G-100D is also quite small, but the faux pentaprism at the top makes it just a bit too big to justify being MFT.
https://petapixel.com/2025/06/28/the-panasonic-lumix-gm-5-is...
If they just remade it with modern AF software, I'd probably carry mine around most every I went. Not to mention what they could do by updating hardware.
I have a GM1, it's truly a standout camera. GM5 makes it even better. It's quite funny nobody wants to attempt similar sizes, even when the market has voted for pocketable cameras.
Especially OM - with all their troubles, if it were me I'd have pivoted the company to sizes that do justice to the mount's inherent size advantage. They have a rich legacy of amazing small cameras (Trip, Pen, XA series, and the overrated mju ii) - yet it's fuji selling an order of magnitude more x-halfs than anything OM is producing.