Some of Matts recent favorites include Arco, Neva, Cocoon, Animal Well, Baldurs Gate 3, and Tears of the Kingdom
If youd prefer to leave nothing to chance, you can also easily make infinite combat steps by combining cards like Sword of Feast and Famine, Druids Repository, or Faeburrow Elder with Najeelas effect
You can use 5 of that mana to put the Elemental onto the battlefield from exile, and just keep going from there
For three mana, Branching Evolution states that if any number of +1/+1 counters would be put on a creature under its owner's control, twice that many counters are put on that creature instead
The latter which I recently made the Top 8 of a Vintage Challenge with on Magic Online, but then an order I made for Modern Dredge arrived, so I decided I needed to write about that instead