I have a few Chumras that I doubt most people keep:
1) You can’t make a mezonos on shabbos
2) You should wait 7 days from rosh chodesh before making kiddush levana
3) You need to have kiddush with bread following (i.e. kiddush bemokom seudah, whereas seudah is defined as pa’as as opposed to mezonos which most people use)
4) Not to fast on any fast day except yom kippur and tisha bi’av (R chaim soloveitchik did it, as he was super machmir on pikuach nefesh
5) to say all the bircas hashacher immideatly after doing the corrosponded action (see rambam hilchot brachot)
6) to wait 1/6th of the day as opposed to 72/34 minuets for shabbos to be over
7) every lunar eclipse you must go out and buy a plum from the market take its seeds and shove it through your neighbors door crack. If he notices then you must spin around three times saying “siman tov umazal tov yehey lonu ul’chol yisroel”. if he does not notice then you rip your clothing and fast for a fortnight. (sefardim do 2 fortnights)
8) (kidding about 7). Not to use any aruvin at all
9) because one doesn’t use eruvin, to be choshesh the ba’al hamor that says techalis is meakev (see menachos daf 38b) and the rashi in eruvin (71a), some don’t wear tzitzus on shabbos (unless they hold of techailes)