In the lore, there's Mechanicum Ships that can fire timeshifting black holes as bullets. I am assuming that DAoT was essentially a Culture-like civ that only perished because they lacked the knowledge of Psykerism. So yeah, they have superior tech to everybody else barring the Old Ones whom no longer exist.
Not sure this is particularly relevant, tho. Just saying DAoT are the apex of tech evolution in the galaxy. The catch is that DAoT is just that: Tech. It knows nothing very little of the warp, and knows nothing of corruption. So...
There's room for (terrible) debate. Fluff 40k DAoT has stuff like a Baneblade being classified as a "light tank," i.e. their heavy tanks were titan-class weapons. And yeah, black hole guns.
On the other hand, Necrons at their peak freely made ridiculous things like the
Celestial Orrery (voodoo doll, but for all the stars in the galaxy), the
World Engine, and the
Breath of the Gods (doomsday device that can harvest energy through time), Pokemonning C'Tan was already mentioned. Also, Necrons at their peak generally had better tech than the Old Ones, as evinced by them beating the Old Ones. And they were directly led by the Void Dragon. So probably more advanced overall, but either would be leaps and bounds beyond anything in the current setting.