Several possible additions:

Artificial detonation of gas giant planets is hypothetically possible (writing a draft about it now).

An impact of a large comet-like body (100-1000 km in size) with the Sun could produce a massive solar flash or flare. 

SETI-attack - we find an alien signal which has a description of hostile AI. 

UAP-related risks, which include alien nanobots, berserkers

A list of different risks connected with extraterrestrial intelligence. 

The Big Rip - exponential acceleration of space expansion, resulting in the destruction of everything within 10 billion years.

A collision with another brane in 4D space.

An encounter with a cloud of supernova remnants containing radioactive elements.

Impact risks: Dark comets.

Impact risks: Passing through a comet's tail filled with many Tunguska-sized objects.

Artificial impact billiards.

Phobos falls on Mars, creating a large debris field that reaches Earth.

Chaotic perturbation of planetary orbits results in a collision with Venus in 100 million years.

High-speed impactors (natural or artificial, with speeds exceeding 100 km/sec) produce nuclear reactions in the atmosphere, resulting in global radioactive contamination.

A small primordial black hole becomes trapped inside Earth.

A neutrino shower from a supernova causes significant DNA damage to most living beings through elastic impacts (I think I saw an article about it).

Space dust from colliding objects blocks the Sun in the ecliptic plane, resulting in a severe "nuclear" winter on Earth.

Gravitational waves from a black hole merger damage Earth.
 

"Rogue celestial body" should also include more commonly encountered interstellar objects, such as Oumuamua. Attempting to detect these objects (and to deflect potential impactors) does not seem obviously futile.