Worst types of lost media?

Lost food. I don't know how they can even be considered lost media, and they're just not interesting in the slightest. Like, I know what's like to think discontinued food tasted good, but is it really a issue if you can't obtain some random Mario tie-in foods or something?

For me it depends, if the story behind the piece of lost media is truly interesting, mysterious, or funny, I will be really into it despite what kind of media it is. However most of the time I find myself not too interested in these types of lost media

1. Lost commercials, especially if they aren't too unique compared to similar commercials for the brand. List of exceptions I had: the lost religious subway commercial.
2. Lost bumpers, most bumpers just announce the next show and aren't too unique. The real interesting lost bumpers are the little shorts that used to air between shows, like the lost "cat news" bumper.
3. Lost pilots that have little-to-no difference to the final show. For example, Blue prints is basically Blues clues but Steve is wearing a different shirt. I'm more interested in pilots like Super Why's, Me and My Friends, and Jimmy Two Shoes because they're so different from the final product. It makes for an interesting mini history lesson on the evolution of their show's productions and an interesting case of "what could have been".
4. Most pilots for unaired shows unless they have an interesting story behind them. I love the Martin and Claudia pilot because of its mysterious story despite being an unaired show. Most other unaired show pilots aren't too interesting to me otherwise.
5. Most lostwave songs, which all have a trend of having similar backstories and sounds. At some point you have to wonder how real any of these songs are. It raises my eyebrow as someone who used to be a vaporwave fan. It makes me think the whole movement as a cheap repeat of the vaporwave trend but with a lost media ARG twist. Just makes me groan. Only exception being Evan Olsen's "So Much Better" from the reply all podcast.
6. NSFL stuff. No exceptions. Why would you even want to see that?

TLDR; Basically anything too plain or NSFL to truly warrant a search I find uninteresting.

Well, I'm not really a SpongeBob fan myself(Akazukin ChaCha fan in the house!), & yeah I agree with you, A Day With SpongeBob really WAS the most unique lost media case for the little sponge. Afterwards, it kind of just became looking for a sea(pun intended) of finding some lost signs of Nickelodeon milking the sponge to its core, such as that Got Milk? ad. Meanwhile I'm waiting for some Akazukin ChaCha lost media to show up on these forums once again(I've talked about Creative Products' English dub as well as the supposed "5th season" that never went past some episode descriptions, but otherwise there doesn't seem to be much lost media, which surprises me because of how little we actually know about Akazukin ChaCha's development compared to even something like Ojamajo Doremi).

EmpLemon videos have sold me on what the appeal of NASCAR is.

Fish McBites lawl

Yeah I like the bumpers with unique voice-acting from characters but they aren't a huge priority for me to find.