There is at least eight permanents of any one color on the battlefield.
An opponent cannot block Rith.
({2} magic symbol) ({G} magic symbol) available.
Steps
Declare Rith and Najeela, if desired, as attackers.
If one or more Warriors attack, Najeela triggers, creating that many 1/1 Warrior creature tokens.
Deal combat damage using Rith.
Rith triggers, causing you to pay ({2} magic symbol) ({G} magic symbol) to create at least eight 1/1 Saproling creature tokens.
Activate Phyrexian Altar five times by sacrificing five Saprolings, adding ({W} magic symbol) ({U} magic symbol) ({B} magic symbol) ({R} magic symbol) ({G} magic symbol) .
Activate Najeela by paying ({W} magic symbol) ({U} magic symbol) ({B} magic symbol) ({R} magic symbol) ({G} magic symbol) , untapping all attacking creatures, giving them trample, lifelink and haste, and gaining an additional combat phase after this one.
Move to your next combat phase.
Repeat steps 1-3 one additional time.
Rith triggers, holding priority, activate Phyrexian Altar three times by sacrificing three Saprolings, adding ({2} magic symbol) ({G} magic symbol) .
Resolve the Rith trigger, causing you to pay ({2} magic symbol) ({G} magic symbol) to create at least eight 1/1 Saproling creature tokens.
Repeat from step 5.
If there are at least nine permanents of any color on the battlefield and/or you control a Warrior that can attack, this combo nets infinite creature tokens and colored mana.