Cars: Anything released without wifi/calling. I dont think any modern electric predates this, but you can convert diesels to friendlier oils or most engines to a run off wood. As a bonus higher trim older cars used a lot less plastic
3D printers: id like to add Sovol, not sure about their more recent ones but their older ones either didnt have wifi or run regular klipper. The SV06/SV06 ACE are also entirelly open source except for the GUI, but you can install other klipper GUIs (theres also a repo with steps to build a minimal Debian install instead of relying on sovols firmware updates)
Routers: GL.iNET Use a modified OpenWRT install out of the box but can be flashed to vanilla OpenWRT through the GUI
Cars: Anything released without wifi/calling. I dont think any modern electric predates this, but you can convert diesels to friendlier oils or most engines to a run off wood. As a bonus higher trim older cars used a lot less plastic
Smartwatch: Pinetime
3D printers: id like to add Sovol, not sure about their more recent ones but their older ones either didnt have wifi or run regular klipper. The SV06/SV06 ACE are also entirelly open source except for the GUI, but you can install other klipper GUIs (theres also a repo with steps to build a minimal Debian install instead of relying on sovols firmware updates)
Routers: GL.iNET Use a modified OpenWRT install out of the box but can be flashed to vanilla OpenWRT through the GUI