Precognition/Alternate Future Display (Samael can see countless possible futures at all times, though his ability to act on them is limited due to he can't pinpointing the exact course of events, though having to account for all the possible, innumerable factors that could lead to an world ending outcome),

The Emperor can see countless possible futures at all times, though his ability to act on them is limited due to pinpointing the exact course of events being hearkened by him to wanting to cross an ocean, though having to account for all the possible, innumerable factors that could lead to such an outcome

Aura (Samael possesses an immensely powerful aura around himself, described frequently as a "sun", so potent that one can be outright blinded by their own minds if they gaze into it. His mere presence can bring normal humans to drop to their knees and worship him as a godlike figure, and even the Supernatural Investigators are not immune to this effect. Furthermore his aura is downright destructive to the forces of Darkness and/or Chaos, banishing all but the strongest without even trying),

Pain Manipulation (If he chooses to, simply looking upon him can severely inhibit even Demons, as their minds are overwhelmed by his painful golden light, which can be a blight on the soul),

Memory Manipulation (Could depart memories of his own past life onto the Tribune Ra, and even show them to him through projecting them in his mind. Can likely also manipulate memories of other individuals as he sees fit),

Weapon Mastery (One of the most proficient weapon users in the entire galaxy, unmatched by even his Divine children in capability. Has likely wielded thousands of weapons from hundreds of cultures, varying in technological level from the most primitive to the most advanced during his eons of life),

Martial Arts (Easily the deadliest living combatant in the entire Imperium of Man. Described as "war perfected" by his son Horus, who even after centuries of fighting alongside him is awed at his power. Horus also commented that his brother Fulgrim would not achieve in a thousand lifetimes what the Emperor could do),