Quoted from Dakine747:
Currently, I have six early solid-state Ballys, all fed from only one power outlet and an Alexa smart plug, so I’m able to power up the entire setup simultaneously. The machines are all completely LED’d. In addition, this same outlet powers five toppers (three of which are glass tube neon), and three glass-tube neon wall signs.
Typical 110-volt US electrical outlets are 15 or 20 amps. A "15-amp" outlet is more common and uses 14 gauge wire and must have a 15-amp circuit breaker. A "20-amp" outlet must have 12-gauge wire and 20-amp circuit breaker.
As long as everything is wried to code, if your circuit breaker is not tripping, then you are good, nothing to worry about.
How much can a single outlet power?
Without a current meter, the only way to know for sure is to look up the power consumption of each machine/device and add them up. Example: A 300 watt machine is roughly going to draw 2.5 amps. I say "roughly" because the voltage is going to vary on geography and local transformers to something between 110 and 125 volts. Also say "roughly" because a machine's power rating is the "worst case" and will vary depending on how many lamps, solenoids, etc. are in use at any given time.
I'd be more worried about the smart plug. The power rating on the Alexa smart plug is 15 amps, and it will likely not have a long life if you're running near the 15-amp limit of your circuit. Otherwise, if you're on a 20-amp circuit and operating everything over 15 amps, the smart plug is on borrowed time.