Who could ever pick just one?
The original ( not PG movie adaptation back to book for kids) The Art Of Racing In The Rain by Garth Stein. It’s very insightful, realistic (except that it’s POV of the family dog), and emotional. Entirely beautiful.
I’ve read many books more than once but this one I’ve read over and over and over again and it makes me cry every time. It’s also changed the way I think about things and how I see life (I reread it so many times to remind myself)
Swan Song by Robert R. McCammon. Post apocalyptic “red scare” era America follows the stories of several main characters that slowly and amazingly all come together, including a little girl who makes things grow (plants, crops, dead trees back to life etc...)
The Watchers by Robert R. McCammon. Again “red scare” era America; a man finds a random, beautiful golden retriever in the woods and take him home to find out he’s exceptionally intelligent. Eventually, he discovers that he was genetically engineered to spy on the Russian leaders ( he was meant to be a “gift” from the American government). And more they made another creature whose base form was once a golden retriever but no longer resembles one...and it hates the dog who gets named Einstein.
The Mortal Instruments series by Cassandra Claire. The move that was made was awful, didn’t follow the books at all, the show that seems to have done better I haven’t seen so I have no opinion. The books are 6 in total with many spin off only one of which I’ve also read and recommend (waiting for all the books from the rest of the spin off to be released so I don’t have to get into them and then have to slowly die waiting for the next books to come out). The spin off I read is called The Infernal Devices. 3 books.
There’s many more I can’t think of right now, enjoy!