Games

Blind Guardian is pretty hit-and-miss: their shit lands somewhere on a spectrum of metal to renaissance-faire lol. Sacred Worlds is another one of my favorites.

All of Metallica's S&M album is solid fucking gold, but the best (imo) song from it almost never gets the spotlight, so it's tragically easy to miss: No Leaf Clover

Avenged Sevenfold isn't symphonic metal, but they've got two songs that at least dip their toes in that water: The Stage, and Little Piece of Heaven.

Epica

If you know Epica you're probably already familiar with Nightwish, but in case your not... well, Nightwish. Most of their music is more similar to Omega than the one I'm about to link, but this specific song is just so fucking weird, I love it: Scaretale. Definitely check out their other songs too!

Essence of Datum / Naxayras

You'd probably like Pelican - kind of ambient rock. Or Russian Circles, which is similar but more mellow.

Mohamed Shawky

Not familiar, and the only Mohamed Shawky's I'm seeing on YouTube are a physicist and an athlete. Judging entirely by the name, I'm guessing it's got some Arabic vibes, and the best I've got there is the first one I linked, Wheel of Time, mostly because of the intro... Antti Martikainen has some Arabic sounding songs - that dude's music is ALL over the place... I recall one being a kind of Arabic metal that I could have SWORN was called "Ancient Worlds" but searching that isn't coming up with anything. He does have Arabic hybrid sci-fi music lol. Skim that dude's channel, and brace for a musical roller coaster.

Rivers of Nihil

Hmm, maybe try Lorna Shore, especially Pain Remains. Lorna Shore is WAY too throaty-howler-monkey-shit for me personally, but fortunately they've got instrumental versions too.