I hope the right cats find you, mythbuster! Today is my shelter volunteer day, and I know there will be a whole different group of cats there this week than there was last week. Cats go fast this time of year, especially kittens. Last week we had four kittens at noon and no kittens at two, which is when I left.
Also putting in an endorsement for chipping. My shelter reunited a cat with his people who had been missing for four years after he got out accidentally! It is briefly unpleasant for the cat (just like getting a shot) but I've held plenty of cats for the procedure and they were all fine afterwards, albeit disgruntled. If you get a collar, make sure it's a breakaway collar to avoid accidental injury to your cat if the collar were to get caught on something. You will also want to monitor collar fit and replace or adjust it if your cat changes size. To check and see if a collar is fitting properly, you should be able to slip one or two fingers under the collar with relative ease while the cat has it on. (I have seen the extreme cases of what happens if people leave a too-tight collar on for a long time, and it's...just take my word for it, okay?)