Does Eastern Orthodoxy teach that there are other Apostles besides the first twelve Apostles, Apostle Paul and the Seventy Apostles?
The word "apostle" simply means "someone who has been appointed to deliver a message". The word "disciple" means "follower" or "student". English-speaking people today rarely use the word "apostle" other than to refer to "Jesus's Twelve Apostles", but it's common to talk about people today as "disciples", or to call followers of any religious leader his "disciples".
So "the twelve apostles" or "the twelve disciples" were a specific group particularly close to Jesus, but they were not the only people who followed Jesus or to whom he assigned jobs. Luke 10:1 says "After these things the Lord appointed seventy others also, and sent them two by two before His face into every city and place where He Himself was about to go." As Jesus gave these people a specific assignment, they were in the strictest sense "apostles".
So not just Orthodox but also Catholics and Protestants believe there were other apostles and disciples besides "the Twelve".
The Orthodox Church gives a number of saints the title "Equal to the Apostles." There's a list of some on Wikipedia:
Notable members of this group include Mary Magdalene; St Nino/Nina, who evangelized the Georgians; Cyril and Methodius, who evangelized the Slavs; and St Patrick.