early top 15

Nowhere near a final list, but so far here it is:

1. Overkill - Ironbound
2. Accept - Blood of Nations
3. Blind Guardian - At the Edge of Time
4. Avantasia - Wicked Symphony/Angel of Babylon (Sorry, but I couldn't just list one of them and it to me is one album)
5. Iron Maiden - The Final Frontier
6. Tarot - Gravity of Light
7. Avenged Sevenfold - Nightmare (I don't care what you people say)
8. Scorpions - Sting in the Tail
9. Ozzy - Scream
10. High on Fire - Snakes of the Divine
11. Ihsahn - After
 
I just checked the Mekong Delta album based on recommendations here. It has most definitely moved up to the top of my To Buy list. This is a really nice surprised.

Are their other albums like this new one?

The others are heavier, thrashier (with one obvious exception) and the singers aren't as good. That said they're all excellent and none of the singers are bad, they're just more in line with what one would expect from a thrash singer. They've had classical influences from the start and have covered several classical pieces going back to their debut. They (well, really he since Mekong Delta is primarily Ralph Huber) have a particular affinity for Mussorgsky. They went so far as to dedicate an entire album to two versions of Mussorgsky's Pictures at an Exhibition (the one really non-thrashy album I mentioned).

I'd suggest finding clips of the earlier material before buying, but if you like thrash and don't require singers the quality of LeMar then by all means check them out. All their pre-return albums (s/t through Pictures) have been remastered and sound good.

NP: Hephystus - Burn the Page