Your selection of wee George raises an issue, because Kramer was most definitely a sidekick. Hence we a situation of co-sidekicks. Or I could cite Groucho Marx who had any number of sidekicks depending on how many of his brothers were sober. And co-sidekicks may in time spawn their own list, for which televisionless-I am the ill-adapted to the purpose.
But I applaud - is this The Sound Of Lesser Hand Clapping? - your contribution and award you an honorary key to the Sidekickdom.