In no particular order, here are my top favorite books (out of 114 total) that I read in 2021. (The hyperlinks will take you to my reviews).
Book #1:

When Breath Becomes Air by Paul Kalanithi
Book #2:

House in the Cerulean Sea by TJ Klune
Book #3:

Hollow Kingdom by Kira Jane Buxton
Book #4:

The Opposite of Love by Julie Buxbaum
Book #5:

The Wednesday Wars by Gary D. Schmidt
Book #6:

Caste by Isabel Wilkerson
Book #7:

The Nothing Man by Catherine Ryan Howard
Book #8:

What Comes After by Joanne Tompkins
Book #9:

The Sweetness of Water by Nathan Harris
Book #10:

The Song of Achilles by Madeline Miller
Book #11:

All the Lonely People by Mike Gayle
Book #12:

The Lincoln Highway by Amor Towles