Rather than re-writing another list of suppliers, I recommend that you check out:
... be sure to check out:
For local msp resources:
Ax-Man is a self-described surplus haven. Great if you need something "now" or if you generate ideas by browsing in a setting that encourages you to combine the visual with the tactile experience of exploring things that you can then hack, re-define, or otherwise transform.
If you have some lead time, surplus places like Electronic Goldmine generally offer the same electronics things only cheaper.
A coveted national resource that is local for us is Digi-Key. Generally parts arrive next day without needing to pay for next day shipping costs. They sell small quantities, are very dependable and have an encyclopedic collection of electronic components.