Mantraschism
Skáld
I don't think they tour since the lead singer passed, but I would love to see them.
It's weird this came up, as this week I've been listening to them a fair amount, in particular their first album. It's been a favorite since it came out.
They never played live at all until AFTER Mike Baker died. They have a few times since then, so hopefully one day they'll get a tour together, or play ProgPower. I absolutely love Shadow Gallery.
Anyway, my picks look much the same as most everyone else's.
Shadow Gallery - Tyranny
Shadow Gallery - Room V
Blind Guardian - Nightfall in Middle-Earth
Symphony X - V: The New Mythology Suite
Iron Maiden - Seventh Son of a Seventh Son
King Diamond - Abigail
King Diamond - "Them"
King Diamond - Conspiracy
Opeth - My Arms, Your Hearse
Emperor - Prometheus - The Discipline of Fire and Demise
Nevermore - Dreaming Neon Black
Rhapsody - Dawn of Victory
Royal Hunt - Paradox
Queensrÿche - Operation: Mindcrime
There might be more, but that's all I can think of for now. Concept albums typically aren't my favorite album format, but when done right, they can be exceptional.