Note that's per instance, not for the amount, so something that triggers often like Soul Warden is better
Reclamation Sage Since every player in Commander runs mana rocks (except that one commenter um, actuallying me, I see you), Reclamation Sage always has a few targets
they also gain a +1/+1 counter, as does Captain America, Team Leader
If you have tons of mana but nothing to do, add more gas
Doing things the way I mentioned simulates how phases work if you were to have a spell , and the sequence is smoother than having to hold full control at all times, meaning your opponent has a hard time knowing if you have something or not
A great example of this is the recent Shivan Dragon Secret Lair card that ran into some controversy regarding the cards artwork