Since the "new" Intellivision is allegedly coming somewhere in the future, I've decided to try and make a concept art for the new controller. Please note that this is not official and shouldn't be mistaken for an official thing. I've simply did this to have fun.
The controller has a keypad, 5 face buttons, 6 triggers, start/select buttons two analog sticks and a d-pad. The "i" button is supposed to be a "home" button, i obviously standing for Intellivision. The gamepad has a whooping 28 buttons. The keypad is there to provide a way to easily emulate old Intellivision games as well as to be used in new ones where some kind of numeric input is needed. This way, the controller bridges the way between old and new and provides a cool way to handle games on the system (if it ever comes out).
Obviously it's just me having fun and actual controller might not look like that, if/when the system comes out, though I'd really would like that. To that end, I release this concept on CC0 license so any controller manufacturer interested in using this is free to do so without paying me royalties (though I'd like to get one as a gift if somebody decides to make an actual controller based on my design, but it's not mandatory).