YouTube shorts and Instagram reels are a rip-off of TikTok.
Live streams. Twitch is built around them, but you can also do them in YouTube and Instagram.
Stories. I don’t even know who did them first, but now they are identical in Facebook, Instagram, and Whatsapp.
I know people that “post” stories on WhatsApp and use it for video conferencing very often. Not my cup of tea, but i think those functions do get used quite often.