2 rivvendare’s double double DR’s 2 hawk striders double couble start of turn buffs , end of go does not stack like that and neither does battle cry so why does DR and SoT effects ,
Depends of the wording of the cards. If it says “extra” then the effect stacks, if you have two cards of them. If it doesnt have the “extra” word, then the effects dont stack if you have two of them