On the forced combat side, Trouble in Pairs and No Mercy are some of the best cards in the category, if youve got around $20 to spend on each
Jetmir, Nexus of Revels [Best Token Commander for Combat Buffs] Best complemented with top dual lands, Jetmir is one of the best token commanders you can build your strategy around
The Angel only costs five mana but Engine is colourless only and can be made with things like Grand Architect more quickly
Doubling Season has a textbook example of a replacement effect: The key word here is instead : Doubling Season overrides the normal effect that would have happened (create X tokens, put Y counters) and replaces it with a different effect (create 2X tokens, put 2Y counters)
Not necessarily in Aggro decks, which dont tend to run discard effects, but rather in Rakdos Midrange
Would you use the alternative commander