This is probably due to human pattern recognition mixed with myth but the various versions of the rule of three come to mind.
I'm not particularly superstitious but I tend to do things three times where it makes sense, and when things come in triplicate I take it as a good sign.
I have a lucky number - 22! I also think 5 and its multiples are lucky; something about them is Strong. I also associate diamonds (especially around circles) with luck; both the symbol and the actual object.
Twix. Cuz one time we went to go get a twix at a football game and our team won. Now I always ask for the 'twix da sorte' ('lucky twix') whenever at a game, especially when our team's losing...
The number 4. I could go in depth about the meaning it has for me, but it's relating to angel numbers and general consistency throughout my life! I usually see it in triples.
I actually have this lucky Beanie Baby that I bring with me to tests & to work sometimes. (& it actually works, trust me!) Outside of that, I have a few little charms that I keep in my purse: my favorites being an angel & a clover. & I've been told that it's lucky to carry foreign money with you, & two dollar bills. Anything can be lucky if you give it meaning, I think. I have this little plastic soldier from Risk that I carry around in my wallet too, and do you think that little piece of plastic is imbued with special luck powers? Probably not, but it makes me feel lucky & I think luck is more of a mindset.
Ladybugs because of what they mean symbiotically, and the number 2 or 22 because 22 was the day twin and I was born. I also like 7 because after twin and I my little (middle) sister was born 7 years after me, and the youngest 7 years after her.