Yes, there were. There seemed to be some very tall groups of people around the Middle East in earlier times. I read a BBC report online which spoke of the discovery of very large skeletons in Jordan, but I have been unable to confirm this. (I also just found a report of one in Saudi Arabia: http://friskodude.blogspot.com/2004/06/mysterious-giant-human-ske_108818267252410645.html, but this has proven to be folklore) This article I found deals quite well with the Biblical evidence for "giants". http://www.evcforum.net/cgi-bin/dm.cgi?action=msg&f=1&t=271&m=1 By the time of Goliath, however, they were in decline. He was one of the last, and was clearly working as a mercenary. However, there were a few around. 2 Samuel 21:16 And Ishbi-Benob, one of the descendants of Rapha, whose bronze spearhead weighed three hundred shekels and who was armed with a new sword , said he would kill David. 2 Samuel 21:19 In another battle with the Philistines at Gob, Elhanan son of Jaare-Oregim the Bethlehemite killed Goliath the Gittite, who had a spear with a shaft like a weaver's rod. (this may be referring to David, whose other name was possibly Elhanan, or else the text should read "brother of Goliath" or else there were two men with the same name from the same tribe, quite normal).

Yes there were. Besides Goliath, there were other unusually large men of the Rephaim, among them being Ishbi-benob, the weight of whose spear was 300 shekels of copper (3.4 kg; 7.5 lb) (2Samuel 21:16) Saph, or Sippai (2Samuel 21:18; 1Chronicles 20:4); Lahmi, Goliath’s brother, “the shaft of whose spear was like the beam of loom workers” (1Ch 20:5); and a man of extraordinary size whose fingers and toes were in sixes, totaling 24 (2 Samuel 21:20).

There are stories, although some come from other versions of the old testament or dead sea scrolls or something (so sorry, wish I had an actual quote for you) that mention Nephilim, or sons of the fallen angels & humans. They are mentioned as being giants and there were definitely more than one that existed. There is speculation that Goliath was/was a descendent of one of these beings.

probably

Yes, the Bible mentions in Numbers 13:33 a group of people called “Nephilim” to whom “ in comparison we seemed like grasshoppers”.