ManageWP is a popular service, which I've signed up for as a trialler but I haven't used it. I think it gets more expensive as youu put in more sites, but am not sure on that. It looked impressive and good enough to update a lot of things automatically and schedule posts. https://managewp.com/
MainWP - similar to above, but you have to install a parent plugin to your HQ site and child plugins to your controlled sites to manage your controlled sites from your HQ site. It's free and open source though. I'm a one man band company and I use mainwp atm due to budget. Seems decent though, but it's a bit strange. Possibly because I'm still noob and lame. https://mainwp.com/ I guess these plugins could be a footprint in a pbn. Man, all the stuff I read about pbns make me paranoid about g00g13.
Socioboard - Indianbill's company owns this program/software and it looks impressive. I am trying the .com version for free for now to what it looks like. There's also the .org version which I am not yet capable to handle alone. I will need to check it out further in the next 6 months for heavy testing. I wish they'd get rid of the annoying support popup. The feed section is nice, I' ve tried and ropped in a youtube link in two niche questions yesterday just for the fun of it from the interface in socioboard. I hope they keep developing the software
Rankwyz - also good for blog management from what i've read so far. life time licence is offered I think, not really sure. Owner has a "closed" thread on the market here http://www.rankwyz.com/ Affiliate seos seem to promote this stuff heavily. Probably because it's great. Don't know the price atm. I believe people use this stuff for t1 blogs. Read more about that op
FCS Networker - this is also popular. Kontent Machine seems to be promoting this heavily. I think it's worth checking out for your purposes here http://www.fcsnetworker.com/ . This is an alternative to rankwyz
Hope this helps