'01 SR5 Failed to Start

I went to start my '01 SR5 2wd this morning, I heard a click and all electrical power went DEAD. I opened the fuse/relay box under the hood and jiggled some of the relays and it powered up. Turned the key and started just fine.
Could I have a relay failing? Which one?
I also wonder if a relay had become slightly unseated and by jiggling it I seated it properly... hmmm

might also be a bad or loose battery connection. i would clean and tighten those and with battery unhooked or key off try unplugging and replugging the relays and fuses under the hood, it will clean the pins a little and you can make sure none of the pins look burned

Thanks, the battery's good and my OCD won't let me have any corrosion on the terminals LOL. I'm very particular about that.
Doesn't the starter relay disable all power to accessories when starting? Just weird the way it had no accessory power until I opened the relay box.
BTW, been running errands and it hasn't repeated the problem. Guess it'll wait till the worst possible time. Murphy's law, y'know.