I know most of what plants I can get for the chameleon. I’m mostly wondering where I can actually get them. Like is there a website that sells fully grown tropical plants or something?
Yes, but the shipping will likely be as much or more than the plants.
So I need to do a complete replacements of plants for my veiled chameleons cage. Most of them died because it’s winter right now. I need to know where can I find replacment plants for my chams cage in up north in ct USA. I usually buy my plants from tropical stores or Home Depot, I haven’t actually checked but I assume that they are out of season for tropical plants.
Check.

AFAIK (I live in the Northeast/Great Lakes area) Home Despot, Lowes, Wallymart, et al stock plants year-round. Some Garden stores may still be open too, depending on what's near enough (We've made day-trips to get plants.

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I've also found the tips in this video quite helpful.
If you're planning on replacing all/most, this would be a good opportunity to plan ahead.
I know you said:
I know most of what plants I can get for the chameleon.
But I don't know exactly what you may or may not know, so apologies in advance.
Safe Plant Lists:
Be sure to read all text & notes.
See also: https://chameleonacademy.com/plants/
IME, it's not just a matter of picking plants off of lists; we have to become amateur botanists to some small degree. Learn each plant candidate's individual requirements (water, soil, feeding, light, etc.), and cross-check & balance against other plants and the enclosure as a whole. E.g. full-sun plants won't do well at the bottom of an enclosure, plants that like dry conditions won't do well if misted several times a day, etc., etc. Some plants are better as hangers; others are better as climbers; a few can be either/both, particularly the vines (pothos, philodendron, inch plant).
I would consult multiple sources on plant care; I've found many discrepancies, and gone with the consensus.