Elvish Archdruid‘s static ability that gives Elves +1/+1 does not affect the Elvish Archdruid itself. This is because the ability specifically states that ‘other Elf creatures get +1/+1.’ However, when an object refers to itself by name it means that object only, unless specified. This means that with two Elvish Archdruids in play, each will give +1/+1 to the other.