I go for musicola.
The robot toy is okay n stuff, but I use it in combination with multi-agent gold, which produces more of them. There is no "normal" way to get rid of it again in undocked worlds, so I eventually run into a robot invasion after some time.
Commedia is confusing and I keep mistaking her for other stuff when I am not ultra careful for that greenish tint, so I keep 'er locked.
Lastly, the rubberballs are pretty good, but in the end I prefer the bondi beach balls because A) I have them and B) they are easier to find again.