Auto stores have generic ones and they are very easy to wire in. 4 wire relay is - ground, from switch, battery voltage, power to the lights
Yep most generic relays will work, pretty basic wiring plan on them. If you don’t want to go that route you can always run new wires and just straight wire it from the switch.
Just go in your local auto parts store and ask for a 4 pin relay for wiring up some fog lights. They are plentiful. Will look something like this.