nonsense words

What nonsense word do you use when you know the name of an object but can’t think of it at the moment? (and is there a word that specifically refers to such nonsense words?)

so far, I have:

thingy, thingamabob, thingamabobber, thingamajig, thingamajiggy, thingamajigit
whatsit, whatchamacalit, whosit
doodad, doodaddy, doodadder, doohickey,
dealie, dealibob, dealibobber

also, do you have a specific nonsense word you use just to refer to a name you can't remember?  especially besides "whosit" ex:  Mr. Thingamabell

/crossposted/