You can find them in my collection post that I’ve linked. But for English Sample Pikachu specifically, look at the English E3 Expo 2001 and Matchprint sections. And the New York Press Conference section is the one you’ve already mentioned. Those three Sample Pikachu are the only English ones I’m aware of. There are also 13 Japanese and 1 Italian Sample Pikachu cards.
Greetz,
Quuador