Mechanical Lifeforms: Arguably, digisapiences, although if we’re being picky, they’re information lifeforms that, from time to time, may choose to inhabit mechanical bodies. Also certain worlds which have been given over to experiments in mechanical ecology, with basic mechanical elements handed a number of simple forms, limited intelligence, and the power to redesign (and randomly “mutate”, within parameters) themselves. Also also, most classes of von Neumann probe, not least the linelayers that expand the wormhole network.
And if we’re allowing nanocyborgs like Alternity’s mechalus into this category, having merged with machines – heritable nanotechnology – at one point in their history, then by the same criterion, we need to include essentially every Imperial citizen-shareholder.