Myself having an obnoxiously large collection of figures, I'll try and give an estimate on the worth of some of them.
The Gamera 1999 figure I bought for about $25 U.S. on Amazon, meaning it's not extremely rare, mostly due to reissues. It's probably the most common Gamera figure available.
The Japanese Burning Godzilla, SpaceGodzilla, Cretaceous King Ghidorah, and Mecha-King Ghidorah are all in probably the $30-$50 U.S. range, with the SpaceGodzilla being the least valuable. The Mecha-King Ghidorah, on the other hand, I have seen being sold for very high prices in some cases.
The Bandai Japan Showa Gigan might fetch a nice price, as I rarely see those sold. The Gigan 2004 is not too rare, as it has been reissued a lot. The old Imperial Godzilla figure is a nice bit of nostalgia, but I have no idea how rare they are anymore. When I was little they were very easy to get, but now I see less and less of them. I'm not sure about the Eleking, but Ultraman figures are generally rarer and more expensive than Godzilla figures, except for the Spark Doll ones.
The M.O.G.U.E.R.A. one can fetch well over $100 U.S., and it's generally pretty valuable. The Showa Anguirus might be in the $70 range, but it's still decently rare. The Baragon 2001 is pretty rare to my knowledge too. The King Caesar is a widely-disliked figure, so it may not be worth too much despite its rarity.
That Heisei Godzilla is interesting because of the blue spines. Generally Heisei Godzilla figures with that mold are generally easy to find, but I don't see too many variants with blue spines, so it could be rare. Destoroyah and Godzilla 1954 would probably net at least $50 U.S. online. That Megaguirus looks like a theater exclusive, in which case it is very valuable and rare.
The Orga is pretty rare, and I've seen it listed on Amazon and eBay for over $200. The Millennium Godzilla is less rare, but still probably could get $50. The drill-hand Kiryu is probably only $20 if that, as it's a reissue and is fairly common. I bought one for $17 U.S. recently. The Heisei Mechagodzilla is moderately rare nowadays, and I see it listed at $30 or higher online.
Well, I hope that helped at least a little. I don't own too many of those figures, but I often scour the web looking for Japanese figures in my price range, and so I've seen a lot of those come up. Overall in terms of figures it looks like you got a pretty nice haul from that auction.
