Angel of Death probably isn't even a top 10 Slayer song for me, so limiting it to just songs better than Black Magic, Chemical Warfare, Necrophiliac, and Postmortem (probably my top 4):
Fight Fire With Fire - ridiculously technical and advanced especially for 1984 while also more aggressive than their competition
For Whom the Bell Tolls - total anthem and classic of epic metal
Fade to Black - peak metal ballad
The Call of Ktulu - ambition and atmosphere still unapproached by most of their progeny today with no gimmicks attached
Master of Puppets - self-evident
The Thing That Should Not Be - this was several years ahead of both death metal in terms of drop-tuned heavy churning and tech-metal like Confessor/Meshuggah in terms of unwieldy rhythms and arrangement
Disposable Heroes - main riff reduced to a single heavily-syncopated open-string note yet they successfully get 8 minutes of intense and thematic thrash out of it
Orion - Ktulu pt 2 except exploring a totally different theme in a rather different way
I guess I'll retract the 'dozen' qualification though I'd say Motorbreath, Jump in the Fire, Escape, Creeping Death, Sanitarium, Damage Inc, Blackened, and One are at least competitive with Slayer's best.
Slayer is obviously great and if being purely numerical about direct copycats of their sound, they still win. But they never had the full package of those eight Metallica songs. You'd have to cherry-pick the greatest individual moments of the Slayer discography, maybe somehow meld the bridge of Necrophiliac, the hardcore break of Kill Again, and the melodic tension of Hallowed Point to make a single song to beat any of those eight.