You can search open jobs, but everyone is doing that.
If you want startups, you can look into PR and press releases about funding.
LinkedIn is great for this. As I wrote in another comment, go to LinkedIn and do an advanced search for some word that applies to your background (say 'Python') and within 30 miles of Philadelphia. You'll get a lot of profiles that come up, and many will currently work for companies that are using Python in your area.
Do a bit of research on those companies that come up, find an employee that does what you do (or a level up, or even a CTO at a small shop), find their email address (or ping thru Linked) and make a simple approach.
"Hey, I am currently exploring some new opportunities and while doing some research I came across $COMPANY. I'm not sure if you are currently hiring or not, but based on what I've read (ADD SOMETHING SPECIFIC HERE TO SHOW YOU DID AT LEAST A BIT OF HOMEWORK ON THEM) I'd certainly be interested in learning a bit more about the company. My background is $BRIEFBACKGROUND. If interested, I'd be happy to buy you a cup of coffee to learn some more."
No it doesn't. I've contacted companies who weren't advertising jobs a few times and it was because I had a specific interest in working at the company in question. In my experience people are usually quite pleased to get these kinds of inquiries, whether or not they have a suitable position. Of course your initial inquiry has to be tailored and not just some kind of generic "gimme a job please" spam.
That aside, who exactly do you think you are? Most people who are going to be applying for jobs are naturally going to be applying for jobs at a bunch of different companies. After all, it would be a bit presumptuous to assume that the first company you contact is going to hire you, and most people are able to identify quite a number of companies where they would probably be happy to work. Is your outfit really so special that you can demand serial monogamy from job applicants?