Been a while since that. Looking back now, the only good one I’ve enjoyed which the Handy can carry is the MIL-MIX PLUS 2 (soft).
The Handy can confidently carry up to ~400g, this toy is at a sweet spot of 304g. It’s also in a cylindral shape that won’t collide with the machine.
There’s also a hard version which didn’t enjoy - it was too narrow and plain in texture.
That’s it for the Handy. There are other toys I could recommend but are all too heavy for it.