- Hominy, dried or canned: never seen it here. I bring dried back from Canada. Not all that easy to find in Vancouver either!
- Epizote: ditto.
- Other chiles: ditto. A few years ago fresh jalapeños showed up in supermarkets for a few months, but they didn’t last long. Every few years I investigate North American websites that could deliver a range of chiles, but I’ve never found anything that works for Taiwan. iHerb used to sell dried ancho chilies, but no longer. As far as I know, we’re stuck with jarred or canned jalapeños, and canned chipotles in adobo, the latter almost always diced. I have bought ancho seeds (yes, so labelled) at the Jianguo Flower Market. I presumably killed those seeds before they had a chance to give me either ancho or poblano chiles.
- Vanilla: vanilla extract available pretty much everywhere, I think. Pods often available in higher-end baking stores & supermarkets (City Super, Jason’s, maybe the Tianmu Carrefour).
- Canned tomatillos: to my surprise, currently regularly available at the two Carrefours I frequent (Danshui & Zhishan-Tianmu). I’ve never seen fresh here. They’re in the “stock up while they’ve got them category”, since they previously vanished for five or six years.
- Not on your list: I’ve seen masa harina the past couple of times I’ve been to the Taipei 101 Jason’s, which is unusual - that’s another ingredient that can disappear for a year or more.
- Implied by your list: I don’t think I’ve ever seen dried black beans here in supermarkets here, or at least the “right” kind. Maybe I saw these for sale at Kook’s (restaurant in Danshui), but I’m not sure. EDIT: I get them from iHerb.
As for processed stuff:
- Guacamole “cups” often available at Costco. They’re not the best but I do buy them because they’re a manageable portion. My wife isn’t fond of guacamole, I can’t get through a whole avocado’s worth on my own, and it’s not a food that keeps well. I’ve also seen jarred guacamole dip but I’ve never bought it.
- For better guacamole: Haas avocados are easier to find than they used to be: most supermarkets stock them, I think, although once in a while they’ll vanish for a month or two.
- Canned refried black beans usually available at the right Carrefours.
- Canned enchilada sauce, both red and green, often available at the right Carrefours, City Super, Jason’s.
See also: