Oh we also have different options. There's Dingsbums, Pinöckel (that's more specific though, I'd say it's for some kind of appendage/button/switch/something protruding) and @demryn what was your word again?
It also depends on your dialect and region :)
@xvarnah it means something like it. A "grej" is a thing and "mackapär" or "mojäng" is basically the same as thingamabob so kind of a thing-thingamabob.
The english language seems particularly rich in these synonyms.
It also depends on your dialect and region :)