There are many choices, here is just one listing:
For a 30A rated motor I would use 3.5mm bullets on the ESC (sockets) to motor (bullets) connections. I like the 3.5mm bullets as a good all around size for motors bigger than 40 grams or so up to over 100 grams. That way I can mix and match my ESCs and motors as much as I want or need to.
For the battery I am a Dean's Ultra person. Or the T-plug cones. On the clones I like the ones with the "X" pattern molded into them as they are easier to get a grip on.
Others will prefer XT60, EC3, APP, or whatever they got started with on batteries. It makes sense to have the same connector on most of your batteries. And the socket or female should be on the battery and the male on the ESC so that you do not have exposed contacts with voltage on them.