The Voyage of the Space Beagle by A. E. Van Vogt. Wikipedia has an article on the novel here.
This is a fixup novel made from four of Van Vogt's novellas. The alien that looks like a cat appears in the first story. He is a Coeurl, the last of his race, and he lives by extracting potassium from the creatures that he kills. The crew initially believe him to be harmless and he kills several of the crew before they manage to outwit him. The original story was called Black Destroyer and was discussed in the question Short story about alien feline beast that kills spacemen, leaches vital substances from their bodies?
The alien cloud appears in the last story. The ship find a jungle planet that turns out to have the cities of a lost civilisation buried under the jungle. It turns out that a being called Anabis made up from a unspecified gas is responsible. Anabis feeds off emotional energy and has found that jungle creatures are the best source of this when they fight, so it has been converting planets to jungle worlds to maximise its source of energy.
The telepathic aliens are the second story. They mean no harm to the ship but their attempts to communicate telepathically with the crew cause damage to human minds. The main protagonist in the book, Grosvenor, manages to communicate with them to stop the damaging attempts at communications.
I confess I remember little about the third story, though the Wikipedia article I linked above gives a brief description of the plot:
In the third section, the ship comes across Ixtl, a scarlet being floating in deep space. It is a vicious survivor of a race that ruled a previous universe before the Big Bang, the creation of our own universe. Ixtl boards the ship, and being obsessed with its own reproduction, kidnaps several crew members in order to implant parasitic eggs in their stomachs. It is eventually tricked into leaving the ship, after all the crew have left the ship temporarily, leaving no prey left for its offspring to feed on.