Writing Magazine run monthly competitions on various themes throughout the year. They also have subscriber-only competitions. More info
I came across this in Writers’ Forum magazine (Dec 2018). A novel-writing competition, sponsored by Your Cat magazine. The first prize is a three-book deal. The genres can be romance, fantasy, historical, thriller or a Christmas story! But get this, there has to be a cat in your story! Yes, you have read right, be sure your novel features a feline to qualify for the competition!
The competition is open to new writers only (unpublished), however your manuscript must be assessed by an editorial service first.
The deadline for this competition is 28 February 2019! Not a great deal of time, would obviously suit someone whose manuscript is READY!
More details can be obtained here: https://www.choc-lit.com/