really REALLY strong licorice
chocolate with a very high cocoa content (there's a bar of chocolate with a 99% cocoa content, which I found enjoyable, but I guess most people might find it too bitter)
Haggis
I agree with OP on the black pudding (Irish housemate at uni introduced it to me), as well as rabbit, spinach and mushrooms :p
And you absolutely MUST try heart, it's the best offal out there in my opinion. It's cheap, lean, very meaty (tastes like the animal from which it came, but stronger, and with a slightly irony taste added in), and versatile.
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I'm not like them, but I can pretend
The sun is gone, but I have a light
The day is done, but I'm having fun
I think I'm dumb, or maybe just happy...