Electronics mounts
Uno R3 (and R4 Minima / WiFi) with the official outline, four ⌀3.2 holes, USB and DC jack positions and the stacking headers.
Solid Vibes StandardElectronics mounts
Breadboard-friendly 43.2 × 17.8 mm Nano with mini-USB; no mounting holes, held by its two 15-pin rows.
Solid Vibes Standard