I want to upgrade the light switches in a room. I have a 3 gang box, two single pole switches and an indicator light for one of them (the basement light switch). The indicator light is its own thing and uses its own space in the box. All I find in the big box stores is switches with built in indicators. But I need to fill three slots in the box. And I would also need the switch cover to have a lens to show when the indicator is on. Can't find that either. What's currently installed is from the 1960s and needs to be replaced. Thanks everyone.
If I am reading your question right what you are looking for is a jewel light, which you won't find in a big box retail store but you should be able to find on line. This is an image of a red jewel light.
If that seems a little more than you want to handle, you might try and install a switch with a lighted handle and buy a wall switch blank for the other slot.
These can be found in some big box hardware stores, usually in white. If not then you can also order these on line.