E&G is good and local.
I picked up the kit of Weather-tite connectors from Summit a while ago. I don't use a whole lot of them, but I periodically restock it.
Besides Parts Express there is Waytek and Delcity. I've also used Wiring Products, which is smaller.
'91 Pickup - Imelda
'08 Tacoma TRD - Donna
"Hey Macarena!" -- Thomas Jefferson