The Copts don't really have a printed catechism in English, at least not that I've seen. The closest we might get in the modern day are probably the handouts given as part of various classes taught by a particular diocese (e.g., the Southern United States diocese had a course on patristics a few years ago), church, or monastery. There is the very old (1892!) catechism of one Fr. Filotheos, which is the earliest that I've been able to find in English, but I wouldn't recommend that one, as the translation was actually made by the Anglicans (for some reason in the late 1800s there was a spate of material by Anglicans about the Coptic Orthodox Church; usually pretty positive, but not necessarily actually reflecting what the Church taught and did and why), and some of the stuff in it seems to have what I would assume is an "Anglican slant" in its wording in a way that seems weird relative to actual Coptic Orthodox writers I've read. Maybe it's just the slightly antiquated English, but I dunno.
Fr. Tadros Malaty wrote an English language introduction to the Coptic Orthodox Church (I think it's just called "Introduction to the Coptic Orthodox Church") in the 1990s that is pretty solid. Again, not a catechism as such, but if you're looking for an entry-level overview in English that is actually understandable (unlike HH Pope Shenouda III's many, many works that clearly did not pass before the eyes of a native English speaker before being printed), you could definitely do worse.
Come to think of it, I do have a little booklet by HG Bp. Sion Manoogian of the Armenian Church. It's about 50 pages and is called "The Armenian Church and Her Teachings", and goes through a bit of the history of Armenian Christianity (e.g., the Armenian translation of the Bible and how it fits in the timeline of other translations), some of the prayers of various Armenian saints like St. Nerses and the theology reflected in them, etc. It's really quite nice, if a bit brief.
From the Syriacs, HH Mor Ignatius Aphrem I († 1957) published a catechism in 1965 (edit: maybe that was the reprinting date for the edition I found on WorldCat, or it was published posthumously; I just noticed this discrepancy; oops), The Shorter Catechism of the Syrian Orthodox Church of Antioch. Apparently it's 20 pages, so they weren't kidding with that title. I've never read it, though.
I'm sure there's something from the Ethiopians and Eritreans, but if there is it's probably in Amharic, Tigrinya, or another Ethio-Semitic language so I can't read it. The few books I've seen from them in English have been more like general histories or explanations of their theology presented in academic settings and terms.