Some EV come with Vehicle-To-Load (V2L) capability. They can usually provide up to ~3.5kW from a mains socket in the vehicle or on a dongle that plugs into the charge port.

A few come with Vehicle-To-Grid (V2G) capability. They can provide more power, tens of kW. They require a box on your house hooked into the breaker panel and plug into the vehicle charge port (like V2L but chunkier).

If you just want emergency power almost all EV have a regular 12V car battery that an inverter could connect to. I’ve done this with my lowly Nissan Leaf and kept essentials (lights, internet, fridge, tv, device chargers) running through several power cuts.

Almost anything pre “digital” era. Not so much because of the lack of electronics and component complexity (fuel injection, CANbus, etc) but because the overall structural and bodywork design of the vehicle is simple. There was no computer aided design enabling super efficient use of space, or added luxuries like noise deadening materials - things that can make installing EV bits tricky.