I know different things need to be diped in a mikva
Theoreticaly does a ice machine need to be dipped in the mikvah? (when its Ice maker is built from stainless steel)
There are opinions that electrical appliances do not require tevila as they are not keilim as well as if an item is not portable it would not require tevila either.
Here is a source that talks about some of the laws in regards to what you must tovel.