Naturally, and as always, I guarantee fabulous success exceeding your wildest dreams. 😊
1) Underground Book Reviews (reviews with an interesting vetting process.) Nice community. A newletter with articles and author interivews. A contest, but they only enter books that have gotten top reviews by their team.
2) Brag Medallion- they award a mark of quality to well written indie books. They interview medallion winners, do some promotion. Rather slow.
3) Awesome Indies Association- quality medallions, with different tiers. The have writing services. I used writers in the group for 2 rounds of editing, developmental and proof-reading, on my second book. Very reasonable prices for the service.
4) Storycartel- you give away free e-books, receive readers' emails and the possibility of unbiased reviews on Amazon and Goodreads. I 'met' a few bloggers, a teacher and other writers through them downloading something I wrote.
5) Onlinebooksclub- Unbiased reviews with s mall reader's fee. It may have gone up recently. I am goodreads friends with a reader I met there. They do promotion, for a fee.
6) Reader's Favorite- reviews and quality medallions. A contest.
7) Wishing Shelf Book Awards- your book will be read by a class or two in England. For adult books they have an adult reader group. You will get the readers/judges comments. And you can have the readers review it on Amazon. There is an award for the best books. Great program, and I have a daydream about doing something similar in the USA based on the model. It is super-slow though. the process takes a year. They have a small vetting process before a book is accepted, I think.
8) YouWriteOn- beta readers. You post chapters/stories. Earn credits by reading and reviewing other people's work. Use those credits to get readers for you. I was dubious, but I found people very thoughtful and honest. It is a time commitment. There is some contest/popularity contest thing there too where the well-received books can get a read from a professional from a major house. Overall, I had a good experience there and if I had time, I would do it again. I haven't done it in a couple of years, so I hope it is still the same.
Beware contests with high fees. Contests in general are dubious. I've listed a couple that I felt were transparent, genuine, and supportive. Reviews are important. Real reviews from real readers. There are organizations that will happily charge a writer a few hundred dollars for a unbiased review. I don't trust them, unless it is something major and establihed like Kirkus. I've never used Kirkus though, so I can't really advise on the return on investment.