I have a Brother P-touch D220 and I kept losing the little paper sheet that lists its symbols and frames. Scrolling the tiny screen one item at a time drove me nuts, so I built Labelarium for myself.

I went through every PDF manual page by page, cropped each symbol, frame and template, and tagged it with everyday words. Search "do not enter" and you find the No entry sign, with the exact keys to press.

My favourite part is the label preview. Type your text, pick the tape, font and frame, and you see the label on real tape colours plus a step-by-step recipe for your model. Follow it blindly and you get the same label every time.

It covers 10 label makers from Brother, DYMO, Brady, NIIMBOT and Phomemo, with how-to guides and a fix for every error message. It works offline and installs like an app on your phone. Free, no account, open source.