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I regret not posting it before Canvas 2025, but hopefully it'll be useful for people playing it in 2026. All letters are 5 pixels tall, and most 3 pixels wide (some 4, a few 5). I've also included a few Cyrillic letters and the digits.
I tried to make it even smaller, but it gets really funky.
I didn't notice Ц in the original post, I thought it's Ч
I didn't include Ч because it's easy to sub it with 4, Volapuk style.