I've read on the forums that you can make your own extracts with VG or PGA, so you could pick many foods that would be appropriate and create a flavoring of them if you want to experiment with different stuff for throat hits.
I have been thinking about what kinds of things could cause a throat hit. We already commonly know about Menthol and red peppers like Cayenne extract. Curious about Habanero, but that is extremely strong. Just in case anyone else wants to try it, here are some things that could do it that I believe would also not be harmful in moderation:
fresh onions, ginger root, black pepper.
I have started a ginger root flavoring. I bought a small piece of ginger (maybe 20 grams or so), "peeled" it like a potato, minced it, and put it in a container and added PGA just over the top. I shook that up and have been letting it sit. I'll let it sit for a day or two, probably use a cocktail masher to mash it a few times during that time, and then strain it with a coffee filter. I'll mix it with some PG and post what it is like.
I attach a picture of my ginger experiment in progress. I'd be interested in anyone's thoughts or concerns regarding it.