Even with a few additions, I’ve found that the options for making a sorcerer are rather slim in 5th Edition. You only have a few choices for your power’s origins. I’ve also really missed playing a summoner. That being said, the summoner I used to play in Pathfinder was greatly different than this. This one is called Living Gateway.
I started messing around with homebrewing a subclass for sorcerer, not based around a single creature you customise like in Pathfinder, but around summoning a large array of weaker creatures with abilities to compliment that.
Anyway, it’s just a work in progress, but I thought I’d share it anyway. It seems to be decent enough to played right now as long as you don’t pass level 4 and start getting 3rd level spell slots.