EDC (everyday carry) this can include pen, notebook, knife, phone, fidget, etc. my most expensive piece that is in my current rotation is my fidget clicker in full brass from unquiet hands. that one chunk of metal and magnets cost me $130
wristwatch revival is a great youtube channel. he buys primarily off of ebay and restores working and non working watches
i collect post apocalyptic books, espicially zombie related books. most are the audio version, my wife swears she will divorce me if i buy any more books, lol
reddit used to have a great fountain pen community. i dont collect myself, bit i do enjoy seeing those beautiful works of art
i collect dice. i really enjoy finding unusual dice via kickstarter. im always on the look out for something that hasnt been done before or unusual shapes. when a new type, i.e. liquid core, comes out i usually wait a month or so to see what the market does. if everyone starts making them then i dont usually add them to my collection. i am also trying to collect all the chessex gemini series dice
gee here is a novel idea, dont let children have access to social media. that would solve a lot of other problems also