There’s familiar web slang to show complete agreement: +1.
It comes from Google+ (yes, a success from a Google social platform!), which was informed from other social sharing and commenting platforms and web forums that have literal up/down voting options to show endorsement.
In my work, I hear lots of people using the same literal phrase in meetings — and on emails and in group chat messages. It has a nice humility to it. It’s the opposite of stuffy and political corporate environments in which people feel the need to blabber just to show value. We all hate when we say something and then someone speaks up just to essentially say the same thing.
On a team that trusts each other, the goal is simply to gain consensus. So if a teammate offers an idea or makes a suggestion that I mostly agree with I’ll say just that: “plus one.” Other teammates do the same. You’ll be amazed by how quickly a meeting can move.
Give it a try.