There’s definitely a market to take in this area since ms visio has basically fallen out of fashion. I’m using miro at the moment but it really falls short in terms of predefined shapes and pictos.
I'd be really interested to hear which icons you're missing. I'm actually just about to push an update that will add a few more icons to the library (i.e. queues, caches, DNS etc). Expect those over the next few hours. Will try to include any suggestions in the next release. Thanks for checking it out!
you can basically take inspirations (aka steal) from what ms visio offered. I haven't used it in a long time, but FWIR the picto & shape library was completely insane. Every single technical fields was there.