If your deck's key engine is a 4cmc commander like Kaalia of the Vast, for example, then you will want to run ramp cards that can get her out faster, which means ramp that is between 0-2cmc so you can cast Kaalia on turn 3 or earlier instead of her usual turn 4
Most of the legends matter stuff is on a handful of underperforming rares though (i.e., Clive's Hideaway, Serah Farron), so dont expect to build around legends specifically
Then cast them with the mad mana making of #1
That ability means that Jafar can always be on the offensive, doing damage and earning lore as he cycles out the same set of Illusion-based characters
I have found the new MageFinder tool incredibly useful as well for ordering a few cards in a go I'll always look on Mage for stock before going anywhere else
Stay safe, and keep healthy