+1 for Concepts. Even more so if Sync is coming. Clean, minimal and fun to use once you get the hang of it.
Additionally, I’m a big fan of www.miro.com which works great on iPad and macOS. Concepts is of course way more powerful if you’re interested in sketching and drawing, while miro shines on the collaboration and sharing side of things.
While I do use both tools, Miro is definitely used more in my case. I’m not fond of subscriptions either but the consulting plan they offer does really enhance the usefulness, imo.